From e4c14fe0cce25be9f5d4e56e6c1fb3b6a0d7d07a Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Fri, 19 Sep 2025 14:16:46 -0400
Subject: [PATCH 01/21] Instantiate plugin_config in plugin_config.py.

---
 plugin_template/plugin_pkg_name/deploy.py            | 3 +--
 plugin_template/plugin_pkg_name/platform_deployer.py | 1 +
 plugin_template/plugin_pkg_name/plugin_config.py     | 5 +++++
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/plugin_template/plugin_pkg_name/deploy.py b/plugin_template/plugin_pkg_name/deploy.py
index c928572..c9ca0f4 100644
--- a/plugin_template/plugin_pkg_name/deploy.py
+++ b/plugin_template/plugin_pkg_name/deploy.py
@@ -7,13 +7,12 @@
 import django_simple_deploy
 
 from {{PluginName}}.platform_deployer import PlatformDeployer
-from .plugin_config import PluginConfig
+from .plugin_config import plugin_config
 
 
 @django_simple_deploy.hookimpl
 def dsd_get_plugin_config():
     """Get platform-specific attributes needed by core."""
-    plugin_config = PluginConfig()
     return plugin_config
 
 
diff --git a/plugin_template/plugin_pkg_name/platform_deployer.py b/plugin_template/plugin_pkg_name/platform_deployer.py
index ea09bff..9e71285 100644
--- a/plugin_template/plugin_pkg_name/platform_deployer.py
+++ b/plugin_template/plugin_pkg_name/platform_deployer.py
@@ -51,6 +51,7 @@ def _add_requirements(self):
 import requests
 
 from . import deploy_messages as platform_msgs
+from .plugin_config import plugin_config
 
 from django_simple_deploy.management.commands.utils import plugin_utils
 from django_simple_deploy.management.commands.utils.plugin_utils import dsd_config
diff --git a/plugin_template/plugin_pkg_name/plugin_config.py b/plugin_template/plugin_pkg_name/plugin_config.py
index 927d3ee..3634fd5 100644
--- a/plugin_template/plugin_pkg_name/plugin_config.py
+++ b/plugin_template/plugin_pkg_name/plugin_config.py
@@ -25,3 +25,8 @@ def __init__(self):
         self.automate_all_supported = {{AutomateAllSupported}}
         self.confirm_automate_all_msg = platform_msgs.confirm_automate_all
         self.platform_name = "{{PlatformName}}"
+
+
+# Create plugin_config once right here. This approach keeps from having to pass the config
+# instance between core, plugins, and these utility functions.
+plugin_config = PluginConfig()
\ No newline at end of file

From 7e7c2ea455d67d3046ea815ef044a25b7dfa8bc9 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Fri, 19 Sep 2025 14:31:17 -0400
Subject: [PATCH 02/21] Adds CLI options, through cli.py and appropriate hook
 implementations.

---
 plugin_template/plugin_pkg_name/cli.py    | 63 +++++++++++++++++++++++
 plugin_template/plugin_pkg_name/deploy.py | 13 +++++
 2 files changed, 76 insertions(+)
 create mode 100644 plugin_template/plugin_pkg_name/cli.py

diff --git a/plugin_template/plugin_pkg_name/cli.py b/plugin_template/plugin_pkg_name/cli.py
new file mode 100644
index 0000000..3d3c150
--- /dev/null
+++ b/plugin_template/plugin_pkg_name/cli.py
@@ -0,0 +1,63 @@
+"""Extends the core django-simple-deploy CLI."""
+
+import json
+import shlex
+import subprocess
+
+from django_simple_deploy.management.commands.utils.plugin_utils import dsd_config
+from django_simple_deploy.management.commands.utils.command_errors import (
+    DSDCommandError,
+)
+
+from .plugin_config import plugin_config
+
+
+class PluginCLI:
+
+    def __init__(self, parser):
+        """Add plugin-specific args."""
+        group_desc = "Plugin-specific CLI args for {{PACKAGE_NAME}}"
+        plugin_group = parser.add_argument_group(
+            title="Options for {{PACKAGE_NAME}}",
+            description = group_desc,
+        )
+
+        # plugin_group.add_argument(
+        #     "--vm-size",
+        #     type=str,
+        #     help="Name for a preset vm-size configuration, ie `shared-cpu-2x`.",
+        #     default="",
+        # )
+
+
+def validate_cli(options):
+    """Validate options that were passed to CLI."""
+
+    # vm_size = options["vm_size"]
+    # _validate_vm_size(vm_size)
+
+    pass
+
+
+# --- Helper functions ---
+
+# def _validate_vm_size(vm_size):
+#     """Validate the vm size arg that was passed."""
+#     if not vm_size:
+#         return
+
+#     if not dsd_config.unit_testing:
+#         cmd = "fly platform vm-sizes --json"
+#         cmd_parts = shlex.split(cmd)
+#         output = subprocess.run(cmd_parts, capture_output=True)
+#         allowed_sizes = list(json.loads(output.stdout).keys())
+#     else:
+#         allowed_sizes = ["shared-cup-1x", "shared-cpu-2x"]
+
+#     if vm_size not in allowed_sizes:
+#         msg = f"The vm-size {vm_size} requested is not available."
+#         msg += f"\n  Allowed sizes: {' '.join(allowed_sizes)}"
+#         raise DSDCommandError(msg)
+
+#     # vm_size is valid. Set the relevant plugin_config attribute.
+#     plugin_config.vm_size = vm_size
\ No newline at end of file
diff --git a/plugin_template/plugin_pkg_name/deploy.py b/plugin_template/plugin_pkg_name/deploy.py
index c9ca0f4..87d6ab3 100644
--- a/plugin_template/plugin_pkg_name/deploy.py
+++ b/plugin_template/plugin_pkg_name/deploy.py
@@ -8,6 +8,7 @@
 
 from {{PluginName}}.platform_deployer import PlatformDeployer
 from .plugin_config import plugin_config
+from .cli import PluginCLI, validate_cli
 
 
 @django_simple_deploy.hookimpl
@@ -16,6 +17,18 @@ def dsd_get_plugin_config():
     return plugin_config
 
 
+@django_simple_deploy.hookimpl
+def dsd_get_plugin_cli(parser):
+    """Get plugin's CLI extension."""
+    plugin_cli = PluginCLI(parser)
+
+
+@django_simple_deploy.hookimpl
+def dsd_validate_cli(options):
+    """Validate and parse plugin-specific CLI args."""
+    validate_cli(options)
+
+
 @django_simple_deploy.hookimpl
 def dsd_deploy():
     """Carry out platform-specific deployment steps."""

From 4f993ce1d42ec3797cb4273cb430d905ede9a0fc Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Fri, 19 Sep 2025 14:39:06 -0400
Subject: [PATCH 03/21] Files for testing cli args.

---
 .../plugin_help_text_sample.txt               |  6 ++++
 .../integration_tests/test_custom_cli_arg.py  | 22 ++++++++++++
 .../integration_tests/test_help_output.py     | 35 +++++++++++++++++++
 3 files changed, 63 insertions(+)
 create mode 100644 plugin_template/tests/integration_tests/reference_files/plugin_help_text_sample.txt
 create mode 100644 plugin_template/tests/integration_tests/test_custom_cli_arg.py
 create mode 100644 plugin_template/tests/integration_tests/test_help_output.py

diff --git a/plugin_template/tests/integration_tests/reference_files/plugin_help_text_sample.txt b/plugin_template/tests/integration_tests/reference_files/plugin_help_text_sample.txt
new file mode 100644
index 0000000..ef17f9c
--- /dev/null
+++ b/plugin_template/tests/integration_tests/reference_files/plugin_help_text_sample.txt
@@ -0,0 +1,6 @@
+Options for dsd-flyio:
+  Full documentation: https://django-simple-deploy.readthedocs.io/en/latest/
+  quick_starts/quick_start_flyio/#customizing-the-deployment
+
+  --vm-size VM_SIZE     Name for a preset vm-size configuration on Fly.io, ie
+                        `shared-cpu-2x`.
\ No newline at end of file
diff --git a/plugin_template/tests/integration_tests/test_custom_cli_arg.py b/plugin_template/tests/integration_tests/test_custom_cli_arg.py
new file mode 100644
index 0000000..c1fcae9
--- /dev/null
+++ b/plugin_template/tests/integration_tests/test_custom_cli_arg.py
@@ -0,0 +1,22 @@
+"""Test a custom plugin-specific CLI arg.
+"""
+
+import pytest
+
+from tests.integration_tests.conftest import tmp_project
+from tests.integration_tests.utils import manage_sample_project as msp
+
+# Skip the default module-level `manage.py deploy call`, so we can call
+# `deploy` with our own set of plugin-specific CLI args.
+pytestmark = pytest.mark.skip_auto_dsd_call
+
+
+# def test_vm_size_arg(tmp_project, request):
+#     """Test that a custom vm size is written to fly.toml."""
+#     cmd = "python manage.py deploy --vm-size shared-cpu-2x"
+#     msp.call_deploy(tmp_project, cmd, platform="fly_io")
+
+#     path = tmp_project / "fly.toml"
+#     contents_fly_toml = path.read_text()
+
+#     assert 'size = "shared-cpu-2x"' in contents_fly_toml
\ No newline at end of file
diff --git a/plugin_template/tests/integration_tests/test_help_output.py b/plugin_template/tests/integration_tests/test_help_output.py
new file mode 100644
index 0000000..73d2a82
--- /dev/null
+++ b/plugin_template/tests/integration_tests/test_help_output.py
@@ -0,0 +1,35 @@
+"""Test the help output when {{PACKAGE_NAME}} is installed.
+
+The core django-simple-deploy library tests its own help output.
+This test checks that plugin-specific options are included in the help output.
+"""
+
+from pathlib import Path
+
+import pytest
+
+from tests.integration_tests.conftest import tmp_project
+from tests.integration_tests.utils import manage_sample_project as msp
+
+# Skip the default module-level `manage.py deploy call`, so we can call
+# `deploy` with our own set of plugin-specific CLI args.
+pytestmark = pytest.mark.skip_auto_dsd_call
+
+
+# def test_plugin_help_output(tmp_project, request):
+#     """Test that {{PACKAGE_NAME}} CLI args are included in help output.
+
+#     Note: When updating this, run `manage.py deploy --help` in a terminal set
+#     to 80 characters wide. That splits help text at the same places as the 
+#     test environment.
+#     On macOS, you can simply run:
+#         $ COLUMNS=80 python manage.py deploy --help
+#     """
+#     cmd = "python manage.py deploy --help"
+#     stdout, stderr = msp.call_deploy(tmp_project, cmd)
+
+#     path_reference = Path(__file__).parent / "reference_files" / "plugin_help_text.txt"
+#     help_lines = path_reference.read_text().splitlines()
+
+#     for line in help_lines:
+#         assert line in stdout

From bc723ba0c79d93ba457dd14cef99feeaaf5c3e33 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Fri, 19 Sep 2025 16:54:58 -0400
Subject: [PATCH 04/21] Include new files in generation process.

---
 plugin_template/plugin_pkg_name/cli.py                        | 4 ++--
 plugin_template/tests/integration_tests/test_help_output.py   | 4 ++--
 .../tests/integration_tests/test_platformname_config.py       | 2 +-
 utils/generator_utils.py                                      | 4 ++++
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/plugin_template/plugin_pkg_name/cli.py b/plugin_template/plugin_pkg_name/cli.py
index 3d3c150..284f074 100644
--- a/plugin_template/plugin_pkg_name/cli.py
+++ b/plugin_template/plugin_pkg_name/cli.py
@@ -16,9 +16,9 @@ class PluginCLI:
 
     def __init__(self, parser):
         """Add plugin-specific args."""
-        group_desc = "Plugin-specific CLI args for {{PACKAGE_NAME}}"
+        group_desc = "Plugin-specific CLI args for {{PackageName}}"
         plugin_group = parser.add_argument_group(
-            title="Options for {{PACKAGE_NAME}}",
+            title="Options for {{PackageName}}",
             description = group_desc,
         )
 
diff --git a/plugin_template/tests/integration_tests/test_help_output.py b/plugin_template/tests/integration_tests/test_help_output.py
index 73d2a82..60a80d0 100644
--- a/plugin_template/tests/integration_tests/test_help_output.py
+++ b/plugin_template/tests/integration_tests/test_help_output.py
@@ -1,4 +1,4 @@
-"""Test the help output when {{PACKAGE_NAME}} is installed.
+"""Test the help output when {{PackageName}} is installed.
 
 The core django-simple-deploy library tests its own help output.
 This test checks that plugin-specific options are included in the help output.
@@ -17,7 +17,7 @@
 
 
 # def test_plugin_help_output(tmp_project, request):
-#     """Test that {{PACKAGE_NAME}} CLI args are included in help output.
+#     """Test that {{PackageName}} CLI args are included in help output.
 
 #     Note: When updating this, run `manage.py deploy --help` in a terminal set
 #     to 80 characters wide. That splits help text at the same places as the 
diff --git a/plugin_template/tests/integration_tests/test_platformname_config.py b/plugin_template/tests/integration_tests/test_platformname_config.py
index 3d74c83..3f3b889 100644
--- a/plugin_template/tests/integration_tests/test_platformname_config.py
+++ b/plugin_template/tests/integration_tests/test_platformname_config.py
@@ -1,4 +1,4 @@
-"""Integration tests for django-simple-deploy, targeting Fly.io."""
+"""Integration tests for django-simple-deploy, targeting {{PlatformName}}."""
 
 import sys
 from pathlib import Path
diff --git a/utils/generator_utils.py b/utils/generator_utils.py
index c872165..ae19701 100644
--- a/utils/generator_utils.py
+++ b/utils/generator_utils.py
@@ -153,11 +153,13 @@ def build_new_plugin(args, plugin_config):
         "developer_resources/README.md",
         "plugin_pkg_name/__init__.py",
         "tests/e2e_tests/__init__.py",
+        "tests/integration_tests/test_custom_cli_arg.py",
         "tests/integration_tests/reference_files/.gitignore",
         "tests/integration_tests/reference_files/Pipfile",
         "tests/integration_tests/reference_files/pyproject.toml",
         "tests/integration_tests/reference_files/requirements.txt",
         "tests/integration_tests/reference_files/settings.py",
+        "tests/integration_tests/reference_files/plugin_help_text_sample.txt",
     ]
 
     for target_file in target_files:
@@ -174,6 +176,7 @@ def build_new_plugin(args, plugin_config):
         "pyproject.toml",
         "tests/conftest.py",
         "tests/integration_tests/test_platformname_config.py",
+         "tests/integration_tests/test_help_output.py",
         "tests/e2e_tests/utils.py",
         "tests/e2e_tests/test_deployment.py",
         "MANIFEST.in",
@@ -181,6 +184,7 @@ def build_new_plugin(args, plugin_config):
         "CHANGELOG.md",
         "LICENSE",
         "plugin_pkg_name/platform_deployer.py",
+        "plugin_pkg_name/cli.py",
         "plugin_pkg_name/deploy.py",
         "plugin_pkg_name/plugin_config.py",
         "plugin_pkg_name/templates/dockerfile_example",

From 2714cb55f7fe203411ce2f5591ffd924859c1ab0 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Fri, 19 Sep 2025 17:09:39 -0400
Subject: [PATCH 05/21] Fix comment.

---
 tests/e2e_tests/test_basic_plugin.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/e2e_tests/test_basic_plugin.py b/tests/e2e_tests/test_basic_plugin.py
index e50b7a3..aea9b5f 100644
--- a/tests/e2e_tests/test_basic_plugin.py
+++ b/tests/e2e_tests/test_basic_plugin.py
@@ -10,7 +10,7 @@
 - This makes an editable install of both django-simple-deploy and the new plugin.
 - If there are issues, you can go the test env and modify both core and the new
   plugin to troubleshoot.
-- If you want to do this, ou may need to set run_core_plugin_tests to False, otherwise
+- If you want to do this, you may need to use `--setup-plugins-only`, otherwise
   the pytest temp dir will be garbage collected because so many temp dirs are being made.
 """
 

From de3a5200247741a0869cf791e2617faf98580a9e Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Fri, 19 Sep 2025 17:33:47 -0400
Subject: [PATCH 06/21] Starting test for custom CLI arg.

---
 tests/e2e_tests/test_custom_cli_arg.py | 70 ++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 tests/e2e_tests/test_custom_cli_arg.py

diff --git a/tests/e2e_tests/test_custom_cli_arg.py b/tests/e2e_tests/test_custom_cli_arg.py
new file mode 100644
index 0000000..7b37227
--- /dev/null
+++ b/tests/e2e_tests/test_custom_cli_arg.py
@@ -0,0 +1,70 @@
+"""Test a plugin that uses a custom CLI arg.
+
+Some of the code that supports a custom CLI is commented out in the generated plugin.
+So, we need to uncomment that code, then run the tests.
+
+This test:
+- Generates a new plugin.
+- Modifies the generated files to enable a custom CLI arg.
+- Modifies platform_deployer.py to use the custom CLI arg in a testable way.
+- Sets up a development environment for django-simple-deploy core.
+- Installs the new plugin to the development environment.
+- Runs the plugin's integration tests, using a `deploy` call that includes the custom CLI arg.
+
+Notes:
+- This makes an editable install of both django-simple-deploy and the new plugin.
+- If there are issues, you can go the test env and modify both core and the new
+  plugin to troubleshoot.
+- If you want to do this, you may need to use `--setup-plugins-only`, otherwise
+  the pytest temp dir will be garbage collected because so many temp dirs are being made.
+"""
+
+from argparse import Namespace
+import subprocess
+import shlex
+
+import pytest
+
+from utils.plugin_config import PluginConfig
+from tests.e2e_tests.utils import e2e_utils
+
+
+# Skip these tests if uv is not available.
+pytestmark = pytest.mark.skipif(
+    not e2e_utils.uv_available(), reason="uv must be installed in order to run e2e tests."
+)
+
+
+def test_custom_cli_arg(get_dev_env, cli_options):
+    """Test a simple plugin config."""
+    dev_env_dir, path_to_python, path_dsd = get_dev_env
+
+    plugin_config = PluginConfig(
+        platform_name = "NewFly",
+        pkg_name = "dsd-newfly",
+        support_automate_all = True,
+        license_name = "eric",
+    )
+    e2e_utils.generate_plugin(get_dev_env, plugin_config)
+
+    # Uncomment CLI-related code.
+    path_plugin_dir = dev_env_dir / plugin_config.pkg_name
+    path_main_dir = path_plugin_dir / plugin_config.pkg_name.replace("-", "_")
+
+    path_cli = path_main_dir / "cli.py"
+    path_platform_deployer = path_main_dir / "platform_deployer.py"
+
+    path_tests = path_plugin_dir / "tests" / "integration_tests"
+    path_test_custom_cli = path_tests/ "test_custom_cli_arg.py"
+    path_test_help = path_tests / "test_help_output.py"
+
+    # Assert these paths all exist.
+    assert all([path_cli.exists(), path_platform_deployer.exists(), path_test_custom_cli.exists(), path_test_help.exists()])
+
+
+
+
+
+
+    if not cli_options.setup_plugins_only:
+        e2e_utils.run_core_plugin_tests(path_dsd, plugin_config, cli_options)
\ No newline at end of file

From b0b5bf8eb515c010b969b6a2383c51bf656c65b1 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Fri, 19 Sep 2025 17:44:46 -0400
Subject: [PATCH 07/21] Uncomments appropriate parts of cli.py in temp test
 env.

---
 tests/e2e_tests/test_custom_cli_arg.py | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/tests/e2e_tests/test_custom_cli_arg.py b/tests/e2e_tests/test_custom_cli_arg.py
index 7b37227..061bba2 100644
--- a/tests/e2e_tests/test_custom_cli_arg.py
+++ b/tests/e2e_tests/test_custom_cli_arg.py
@@ -61,10 +61,32 @@ def test_custom_cli_arg(get_dev_env, cli_options):
     # Assert these paths all exist.
     assert all([path_cli.exists(), path_platform_deployer.exists(), path_test_custom_cli.exists(), path_test_help.exists()])
 
+    # cli.py
+    line_nums = [25, 26, 27, 28, 29, 30, 36, 37, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63]
+    uncomment_lines(path_cli, line_nums)
 
 
 
 
 
     if not cli_options.setup_plugins_only:
-        e2e_utils.run_core_plugin_tests(path_dsd, plugin_config, cli_options)
\ No newline at end of file
+        e2e_utils.run_core_plugin_tests(path_dsd, plugin_config, cli_options)
+
+# --- Helper functions ---
+
+def uncomment_lines(path, line_nums):
+    """Uncomment the given lines in a file.
+
+    # DEV: This function should parse a string like "25-30, 36-37, 44-63"
+    """
+    lines = path.read_text().splitlines()
+    new_lines = []
+
+    for line_num, line in enumerate(lines, start=1):
+        if line_num in line_nums:
+            new_lines.append(line.replace("# ", ""))
+        else:
+            new_lines.append(line)
+
+    new_contents = "\n".join(new_lines)
+    path.write_text(new_contents)

From a217a7a23a9a184d8cd91735f5b458a05f5d8c49 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Fri, 19 Sep 2025 22:24:17 -0400
Subject: [PATCH 08/21] Helper function to get list of lines to uncomment.

---
 tests/e2e_tests/test_custom_cli_arg.py | 27 +++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/tests/e2e_tests/test_custom_cli_arg.py b/tests/e2e_tests/test_custom_cli_arg.py
index 061bba2..ac24f57 100644
--- a/tests/e2e_tests/test_custom_cli_arg.py
+++ b/tests/e2e_tests/test_custom_cli_arg.py
@@ -62,8 +62,8 @@ def test_custom_cli_arg(get_dev_env, cli_options):
     assert all([path_cli.exists(), path_platform_deployer.exists(), path_test_custom_cli.exists(), path_test_help.exists()])
 
     # cli.py
-    line_nums = [25, 26, 27, 28, 29, 30, 36, 37, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63]
-    uncomment_lines(path_cli, line_nums)
+    line_num_str = "25-30, 36-37, 44-63"
+    uncomment_lines(path_cli, line_num_str)
 
 
 
@@ -74,14 +74,13 @@ def test_custom_cli_arg(get_dev_env, cli_options):
 
 # --- Helper functions ---
 
-def uncomment_lines(path, line_nums):
+def uncomment_lines(path, line_num_str):
     """Uncomment the given lines in a file.
-
-    # DEV: This function should parse a string like "25-30, 36-37, 44-63"
     """
     lines = path.read_text().splitlines()
     new_lines = []
 
+    line_nums = _get_line_nums(line_num_str)
     for line_num, line in enumerate(lines, start=1):
         if line_num in line_nums:
             new_lines.append(line.replace("# ", ""))
@@ -90,3 +89,21 @@ def uncomment_lines(path, line_nums):
 
     new_contents = "\n".join(new_lines)
     path.write_text(new_contents)
+
+
+def _get_line_nums(line_num_str):
+    """Get list of lines from a string like "25-30, 36-37, 44-63"."""
+    range_strs = line_num_str.split(",")
+
+    line_nums = []
+    for range_str in range_strs:
+        if "-" not in range_str:
+            line_nums.append(int(range_str))
+            continue
+
+        start, end = range_str.split("-")
+        start, end = int(start), int(end)
+        line_nums += list(range(start, end+1))
+
+    return line_nums
+

From 21ffb8b672d1cfd8eb1ba298428ddd053b9cda33 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sat, 20 Sep 2025 06:50:36 -0400
Subject: [PATCH 09/21] Uncomments test files.

---
 tests/e2e_tests/test_custom_cli_arg.py | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/tests/e2e_tests/test_custom_cli_arg.py b/tests/e2e_tests/test_custom_cli_arg.py
index ac24f57..e2ab125 100644
--- a/tests/e2e_tests/test_custom_cli_arg.py
+++ b/tests/e2e_tests/test_custom_cli_arg.py
@@ -57,13 +57,23 @@ def test_custom_cli_arg(get_dev_env, cli_options):
     path_tests = path_plugin_dir / "tests" / "integration_tests"
     path_test_custom_cli = path_tests/ "test_custom_cli_arg.py"
     path_test_help = path_tests / "test_help_output.py"
+    path_help_reference_sample = path_tests / "reference_files" / "plugin_help_text_sample.txt"
 
     # Assert these paths all exist.
     assert all([path_cli.exists(), path_platform_deployer.exists(), path_test_custom_cli.exists(), path_test_help.exists()])
 
-    # cli.py
-    line_num_str = "25-30, 36-37, 44-63"
-    uncomment_lines(path_cli, line_num_str)
+    # Uncomment lines from relevant files.
+    uncomment_lines(path_cli, "25-30, 36-37, 44-63")
+    uncomment_lines(path_test_custom_cli, "14-22")
+    uncomment_lines(path_test_help, "19-35")
+
+    # Make a reference file for the help output.
+    path_help_reference = path_tests / "reference_files" / "plugin_help_text.txt"
+    contents = path_help_reference_sample.read_text()
+    new_contents = contents.replace("Fly.io", plugin_config.pkg_name)
+    new_contents = contents.replace("dsd-flyio", plugin_config.pkg_name)
+    path_help_reference.write_text(new_contents)
+    # DEF: Run test, fail, copy correct help output.
 
 
 
@@ -106,4 +116,3 @@ def _get_line_nums(line_num_str):
         line_nums += list(range(start, end+1))
 
     return line_nums
-

From ad792a1a2d15e3c318cfe1459fbbd8a5da315c48 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 09:57:12 -0400
Subject: [PATCH 10/21] Reference file for help output with a custom CLI arg.

---
 pytest.ini                                    |  2 ++
 .../help_output_vm_size_arg.txt               |  5 ++++
 tests/e2e_tests/test_custom_cli_arg.py        | 25 ++++++++-----------
 tests/e2e_tests/utils/e2e_utils.py            |  2 +-
 4 files changed, 18 insertions(+), 16 deletions(-)
 create mode 100644 tests/e2e_tests/reference_files/help_output_vm_size_arg.txt

diff --git a/pytest.ini b/pytest.ini
index 62ff2f7..5692240 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -12,3 +12,5 @@ norecursedirs =
 
 addopts = --import-mode=importlib
 pythonpath = .
+
+tmp_path_retention_count = 10
diff --git a/tests/e2e_tests/reference_files/help_output_vm_size_arg.txt b/tests/e2e_tests/reference_files/help_output_vm_size_arg.txt
new file mode 100644
index 0000000..79b8a83
--- /dev/null
+++ b/tests/e2e_tests/reference_files/help_output_vm_size_arg.txt
@@ -0,0 +1,5 @@
+Options for dsd-newfly:
+  Plugin-specific CLI args for dsd-newfly
+
+  --vm-size BUGGER     Name for a preset vm-size configuration, ie `shared-
+                        cpu-2x`.
\ No newline at end of file
diff --git a/tests/e2e_tests/test_custom_cli_arg.py b/tests/e2e_tests/test_custom_cli_arg.py
index e2ab125..9de8576 100644
--- a/tests/e2e_tests/test_custom_cli_arg.py
+++ b/tests/e2e_tests/test_custom_cli_arg.py
@@ -22,6 +22,8 @@
 from argparse import Namespace
 import subprocess
 import shlex
+import shutil
+from pathlib import Path
 
 import pytest
 
@@ -55,29 +57,22 @@ def test_custom_cli_arg(get_dev_env, cli_options):
     path_platform_deployer = path_main_dir / "platform_deployer.py"
 
     path_tests = path_plugin_dir / "tests" / "integration_tests"
-    path_test_custom_cli = path_tests/ "test_custom_cli_arg.py"
+    path_test_custom_cli = path_tests / "test_custom_cli_arg.py"
     path_test_help = path_tests / "test_help_output.py"
-    path_help_reference_sample = path_tests / "reference_files" / "plugin_help_text_sample.txt"
 
     # Assert these paths all exist.
     assert all([path_cli.exists(), path_platform_deployer.exists(), path_test_custom_cli.exists(), path_test_help.exists()])
 
     # Uncomment lines from relevant files.
     uncomment_lines(path_cli, "25-30, 36-37, 44-63")
-    uncomment_lines(path_test_custom_cli, "14-22")
+    # uncomment_lines(path_test_custom_cli, "14-22")
     uncomment_lines(path_test_help, "19-35")
 
-    # Make a reference file for the help output.
-    path_help_reference = path_tests / "reference_files" / "plugin_help_text.txt"
-    contents = path_help_reference_sample.read_text()
-    new_contents = contents.replace("Fly.io", plugin_config.pkg_name)
-    new_contents = contents.replace("dsd-flyio", plugin_config.pkg_name)
-    path_help_reference.write_text(new_contents)
-    # DEF: Run test, fail, copy correct help output.
-
-
-
-
+    # Copy reference file for help output to new plugin.
+    path_help_reference = Path(__file__).parent / "reference_files" / "help_output_vm_size_arg.txt"
+    assert path_help_reference.exists()
+    path_help_reference_plugin = path_tests / "reference_files" / "plugin_help_text.txt"
+    shutil.copyfile(path_help_reference, path_help_reference_plugin)
 
     if not cli_options.setup_plugins_only:
         e2e_utils.run_core_plugin_tests(path_dsd, plugin_config, cli_options)
@@ -93,7 +88,7 @@ def uncomment_lines(path, line_num_str):
     line_nums = _get_line_nums(line_num_str)
     for line_num, line in enumerate(lines, start=1):
         if line_num in line_nums:
-            new_lines.append(line.replace("# ", ""))
+            new_lines.append(line.replace("# ", "", count=1))
         else:
             new_lines.append(line)
 
diff --git a/tests/e2e_tests/utils/e2e_utils.py b/tests/e2e_tests/utils/e2e_utils.py
index 9bad2c5..770200f 100644
--- a/tests/e2e_tests/utils/e2e_utils.py
+++ b/tests/e2e_tests/utils/e2e_utils.py
@@ -75,7 +75,7 @@ def get_core_plugin_test_cmd(path_dsd, cli_options, platform_name_lower):
         cmd = f"cd {path_dsd.as_posix()} && source .venv/bin/activate && pytest"
     else:
         # Only run the new plugin's integration tests.
-        cmd = f"cd {path_dsd.as_posix()} && source .venv/bin/activate && pytest -k {test_filename}"
+        cmd = f"cd {path_dsd.as_posix()} && source .venv/bin/activate && pytest -k {test_filename} -k test_help_output.py"
 
     return cmd
 

From 7696b309e036f1bb166806a373468649061cda7b Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 10:14:59 -0400
Subject: [PATCH 11/21] Print output of subprocess tests.

---
 tests/e2e_tests/utils/e2e_utils.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/e2e_tests/utils/e2e_utils.py b/tests/e2e_tests/utils/e2e_utils.py
index 770200f..b4000a4 100644
--- a/tests/e2e_tests/utils/e2e_utils.py
+++ b/tests/e2e_tests/utils/e2e_utils.py
@@ -61,6 +61,7 @@ def run_core_plugin_tests(path_dsd, plugin_config, cli_options):
 
     output = subprocess.run(cmd, capture_output=True,shell=True)
     stdout = output.stdout.decode()
+    print(stdout)
 
     assert "[100%]" in stdout
     check_core_plugin_tests(stdout, cli_options)

From 94b5c00ea4dbc67bd4525850ced8f42e4dc42e4c Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 10:19:26 -0400
Subject: [PATCH 12/21] Check for failure in output, not '100%'.

---
 tests/e2e_tests/utils/e2e_utils.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/e2e_tests/utils/e2e_utils.py b/tests/e2e_tests/utils/e2e_utils.py
index b4000a4..0aa20a3 100644
--- a/tests/e2e_tests/utils/e2e_utils.py
+++ b/tests/e2e_tests/utils/e2e_utils.py
@@ -63,7 +63,7 @@ def run_core_plugin_tests(path_dsd, plugin_config, cli_options):
     stdout = output.stdout.decode()
     print(stdout)
 
-    assert "[100%]" in stdout
+    assert "FAILURE" not in stdout
     check_core_plugin_tests(stdout, cli_options)
 
 

From 8adb0c7f6af4c0a64e80c227c9e9ca93f0ac7542 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 10:27:48 -0400
Subject: [PATCH 13/21] FAILURES -> FAILED

---
 tests/e2e_tests/utils/e2e_utils.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/e2e_tests/utils/e2e_utils.py b/tests/e2e_tests/utils/e2e_utils.py
index 0aa20a3..9876b56 100644
--- a/tests/e2e_tests/utils/e2e_utils.py
+++ b/tests/e2e_tests/utils/e2e_utils.py
@@ -63,7 +63,7 @@ def run_core_plugin_tests(path_dsd, plugin_config, cli_options):
     stdout = output.stdout.decode()
     print(stdout)
 
-    assert "FAILURE" not in stdout
+    assert "FAILED" not in stdout
     check_core_plugin_tests(stdout, cli_options)
 
 

From 9b2ac45622a8d9740ba71f8d7af6f551bffa02d1 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 10:34:31 -0400
Subject: [PATCH 14/21] Correct reference file.

---
 tests/e2e_tests/reference_files/help_output_vm_size_arg.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/e2e_tests/reference_files/help_output_vm_size_arg.txt b/tests/e2e_tests/reference_files/help_output_vm_size_arg.txt
index 79b8a83..204759a 100644
--- a/tests/e2e_tests/reference_files/help_output_vm_size_arg.txt
+++ b/tests/e2e_tests/reference_files/help_output_vm_size_arg.txt
@@ -1,5 +1,5 @@
 Options for dsd-newfly:
   Plugin-specific CLI args for dsd-newfly
 
-  --vm-size BUGGER     Name for a preset vm-size configuration, ie `shared-
+  --vm-size VM_SIZE     Name for a preset vm-size configuration, ie `shared-
                         cpu-2x`.
\ No newline at end of file

From 0dd17b5e2dc11ef0618b33eeca7004262cc08111 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 10:39:02 -0400
Subject: [PATCH 15/21] Message clarifying in test output that generated plugin
 is being modified.

---
 tests/e2e_tests/test_custom_cli_arg.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tests/e2e_tests/test_custom_cli_arg.py b/tests/e2e_tests/test_custom_cli_arg.py
index 9de8576..004ba60 100644
--- a/tests/e2e_tests/test_custom_cli_arg.py
+++ b/tests/e2e_tests/test_custom_cli_arg.py
@@ -49,6 +49,9 @@ def test_custom_cli_arg(get_dev_env, cli_options):
     )
     e2e_utils.generate_plugin(get_dev_env, plugin_config)
 
+    msg = "\n*** Modifying plugin code to use the custom CLI arg that's commented out by default. ***\n"
+    print(msg)
+
     # Uncomment CLI-related code.
     path_plugin_dir = dev_env_dir / plugin_config.pkg_name
     path_main_dir = path_plugin_dir / plugin_config.pkg_name.replace("-", "_")

From e4be221d114cde540560d233ab50e038c2c54a81 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 10:59:26 -0400
Subject: [PATCH 16/21] Modifies plugin's platform_deployer.py to exercise the
 example custom CLI arg.

---
 .../e2e_tests/reference_files/add_fly_toml.py |  8 ++++++
 tests/e2e_tests/test_custom_cli_arg.py        | 27 +++++++++++++++++--
 tests/e2e_tests/utils/e2e_utils.py            |  2 +-
 3 files changed, 34 insertions(+), 3 deletions(-)
 create mode 100644 tests/e2e_tests/reference_files/add_fly_toml.py

diff --git a/tests/e2e_tests/reference_files/add_fly_toml.py b/tests/e2e_tests/reference_files/add_fly_toml.py
new file mode 100644
index 0000000..15c2f79
--- /dev/null
+++ b/tests/e2e_tests/reference_files/add_fly_toml.py
@@ -0,0 +1,8 @@
+        # This is a dummy block to write a fly.toml file with only the 
+        # text needed to pass the test_custom_cli_arg.py test. It is 
+        # not a valid fly.toml file.
+        path = dsd_config.project_root / "fly.toml"
+
+        contents = "Dummy fly.toml file."
+        contents += '\n\nThe text \n\nsize = "shared-cpu-2x"\n\n appears in this file.\n'
+        plugin_utils.add_file(path, contents)
\ No newline at end of file
diff --git a/tests/e2e_tests/test_custom_cli_arg.py b/tests/e2e_tests/test_custom_cli_arg.py
index 004ba60..873ffef 100644
--- a/tests/e2e_tests/test_custom_cli_arg.py
+++ b/tests/e2e_tests/test_custom_cli_arg.py
@@ -68,15 +68,17 @@ def test_custom_cli_arg(get_dev_env, cli_options):
 
     # Uncomment lines from relevant files.
     uncomment_lines(path_cli, "25-30, 36-37, 44-63")
-    # uncomment_lines(path_test_custom_cli, "14-22")
+    uncomment_lines(path_test_custom_cli, "14-22")
     uncomment_lines(path_test_help, "19-35")
 
     # Copy reference file for help output to new plugin.
     path_help_reference = Path(__file__).parent / "reference_files" / "help_output_vm_size_arg.txt"
-    assert path_help_reference.exists()
     path_help_reference_plugin = path_tests / "reference_files" / "plugin_help_text.txt"
     shutil.copyfile(path_help_reference, path_help_reference_plugin)
 
+    # Modify plugin's platform_deployer.py file to pass the uncommented test_custom_cli_arg.py file.
+    _write_add_fly_toml(path_platform_deployer)
+
     if not cli_options.setup_plugins_only:
         e2e_utils.run_core_plugin_tests(path_dsd, plugin_config, cli_options)
 
@@ -114,3 +116,24 @@ def _get_line_nums(line_num_str):
         line_nums += list(range(start, end+1))
 
     return line_nums
+
+
+def _write_add_fly_toml(path_platform_deployer):
+    """Add code to platform_deployer that writes a fly.toml file to pass test_custom_cli_arg.py."""
+    target_string = "# Configure project for deployment to NewFly"
+
+    lines = path_platform_deployer.read_text().splitlines()
+
+    new_lines = []
+    for line in lines:
+        if target_string not in line:
+            new_lines.append(line)
+            continue
+
+        # This only runs once in the loop.
+        path_fly_toml_block = Path(__file__).parent / "reference_files" / "add_fly_toml.py"
+        fly_toml_lines = path_fly_toml_block.read_text().splitlines()
+        new_lines += fly_toml_lines
+
+    new_contents = "\n".join(new_lines)
+    path_platform_deployer.write_text(new_contents)
diff --git a/tests/e2e_tests/utils/e2e_utils.py b/tests/e2e_tests/utils/e2e_utils.py
index 9876b56..0396f17 100644
--- a/tests/e2e_tests/utils/e2e_utils.py
+++ b/tests/e2e_tests/utils/e2e_utils.py
@@ -76,7 +76,7 @@ def get_core_plugin_test_cmd(path_dsd, cli_options, platform_name_lower):
         cmd = f"cd {path_dsd.as_posix()} && source .venv/bin/activate && pytest"
     else:
         # Only run the new plugin's integration tests.
-        cmd = f"cd {path_dsd.as_posix()} && source .venv/bin/activate && pytest -k {test_filename} -k test_help_output.py"
+        cmd = f"cd {path_dsd.as_posix()} && source .venv/bin/activate && pytest -k {test_filename} -k test_help_output.py -k test_custom_cli_arg.py"
 
     return cmd
 

From 5a85b9713f1b90848cdde4653ea2a67be5452274 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 13:51:49 -0400
Subject: [PATCH 17/21] Distinct name for test of plugin cli.

---
 tests/e2e_tests/{test_custom_cli_arg.py => test_plugin_cli.py} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename tests/e2e_tests/{test_custom_cli_arg.py => test_plugin_cli.py} (100%)

diff --git a/tests/e2e_tests/test_custom_cli_arg.py b/tests/e2e_tests/test_plugin_cli.py
similarity index 100%
rename from tests/e2e_tests/test_custom_cli_arg.py
rename to tests/e2e_tests/test_plugin_cli.py

From 5ef550e503612c750391a9c482abb9d960eef4bc Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 14:20:44 -0400
Subject: [PATCH 18/21] Update reference plugins for integration tests.

---
 .../dsd-newfly-no-space/dsd_newfly/cli.py     | 63 +++++++++++++++++++
 .../dsd-newfly-no-space/dsd_newfly/deploy.py  | 16 ++++-
 .../dsd_newfly/platform_deployer.py           |  1 +
 .../dsd_newfly/plugin_config.py               |  5 ++
 .../plugin_help_text_sample.txt               |  6 ++
 .../integration_tests/test_custom_cli_arg.py  | 22 +++++++
 .../integration_tests/test_help_output.py     | 35 +++++++++++
 .../integration_tests/test_newfly_config.py   |  2 +-
 8 files changed, 147 insertions(+), 3 deletions(-)
 create mode 100644 tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/cli.py
 create mode 100644 tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/reference_files/plugin_help_text_sample.txt
 create mode 100644 tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_custom_cli_arg.py
 create mode 100644 tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_help_output.py

diff --git a/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/cli.py b/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/cli.py
new file mode 100644
index 0000000..a438a9a
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/cli.py
@@ -0,0 +1,63 @@
+"""Extends the core django-simple-deploy CLI."""
+
+import json
+import shlex
+import subprocess
+
+from django_simple_deploy.management.commands.utils.plugin_utils import dsd_config
+from django_simple_deploy.management.commands.utils.command_errors import (
+    DSDCommandError,
+)
+
+from .plugin_config import plugin_config
+
+
+class PluginCLI:
+
+    def __init__(self, parser):
+        """Add plugin-specific args."""
+        group_desc = "Plugin-specific CLI args for dsd-newfly"
+        plugin_group = parser.add_argument_group(
+            title="Options for dsd-newfly",
+            description = group_desc,
+        )
+
+        # plugin_group.add_argument(
+        #     "--vm-size",
+        #     type=str,
+        #     help="Name for a preset vm-size configuration, ie `shared-cpu-2x`.",
+        #     default="",
+        # )
+
+
+def validate_cli(options):
+    """Validate options that were passed to CLI."""
+
+    # vm_size = options["vm_size"]
+    # _validate_vm_size(vm_size)
+
+    pass
+
+
+# --- Helper functions ---
+
+# def _validate_vm_size(vm_size):
+#     """Validate the vm size arg that was passed."""
+#     if not vm_size:
+#         return
+
+#     if not dsd_config.unit_testing:
+#         cmd = "fly platform vm-sizes --json"
+#         cmd_parts = shlex.split(cmd)
+#         output = subprocess.run(cmd_parts, capture_output=True)
+#         allowed_sizes = list(json.loads(output.stdout).keys())
+#     else:
+#         allowed_sizes = ["shared-cup-1x", "shared-cpu-2x"]
+
+#     if vm_size not in allowed_sizes:
+#         msg = f"The vm-size {vm_size} requested is not available."
+#         msg += f"\n  Allowed sizes: {' '.join(allowed_sizes)}"
+#         raise DSDCommandError(msg)
+
+#     # vm_size is valid. Set the relevant plugin_config attribute.
+#     plugin_config.vm_size = vm_size
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/deploy.py b/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/deploy.py
index f822cc1..f3897df 100644
--- a/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/deploy.py
+++ b/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/deploy.py
@@ -7,16 +7,28 @@
 import django_simple_deploy
 
 from dsd_newfly.platform_deployer import PlatformDeployer
-from .plugin_config import PluginConfig
+from .plugin_config import plugin_config
+from .cli import PluginCLI, validate_cli
 
 
 @django_simple_deploy.hookimpl
 def dsd_get_plugin_config():
     """Get platform-specific attributes needed by core."""
-    plugin_config = PluginConfig()
     return plugin_config
 
 
+@django_simple_deploy.hookimpl
+def dsd_get_plugin_cli(parser):
+    """Get plugin's CLI extension."""
+    plugin_cli = PluginCLI(parser)
+
+
+@django_simple_deploy.hookimpl
+def dsd_validate_cli(options):
+    """Validate and parse plugin-specific CLI args."""
+    validate_cli(options)
+
+
 @django_simple_deploy.hookimpl
 def dsd_deploy():
     """Carry out platform-specific deployment steps."""
diff --git a/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/platform_deployer.py b/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/platform_deployer.py
index 0609911..2a8b6a1 100644
--- a/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/platform_deployer.py
+++ b/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/platform_deployer.py
@@ -51,6 +51,7 @@ def _add_requirements(self):
 import requests
 
 from . import deploy_messages as platform_msgs
+from .plugin_config import plugin_config
 
 from django_simple_deploy.management.commands.utils import plugin_utils
 from django_simple_deploy.management.commands.utils.plugin_utils import dsd_config
diff --git a/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/plugin_config.py b/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/plugin_config.py
index 30538aa..5dd5003 100644
--- a/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/plugin_config.py
+++ b/tests/integration_tests/reference_files/dsd-newfly-no-space/dsd_newfly/plugin_config.py
@@ -25,3 +25,8 @@ def __init__(self):
         self.automate_all_supported = True
         self.confirm_automate_all_msg = platform_msgs.confirm_automate_all
         self.platform_name = "NewFly"
+
+
+# Create plugin_config once right here. This approach keeps from having to pass the config
+# instance between core, plugins, and these utility functions.
+plugin_config = PluginConfig()
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/reference_files/plugin_help_text_sample.txt b/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/reference_files/plugin_help_text_sample.txt
new file mode 100644
index 0000000..ef17f9c
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/reference_files/plugin_help_text_sample.txt
@@ -0,0 +1,6 @@
+Options for dsd-flyio:
+  Full documentation: https://django-simple-deploy.readthedocs.io/en/latest/
+  quick_starts/quick_start_flyio/#customizing-the-deployment
+
+  --vm-size VM_SIZE     Name for a preset vm-size configuration on Fly.io, ie
+                        `shared-cpu-2x`.
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_custom_cli_arg.py b/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_custom_cli_arg.py
new file mode 100644
index 0000000..c1fcae9
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_custom_cli_arg.py
@@ -0,0 +1,22 @@
+"""Test a custom plugin-specific CLI arg.
+"""
+
+import pytest
+
+from tests.integration_tests.conftest import tmp_project
+from tests.integration_tests.utils import manage_sample_project as msp
+
+# Skip the default module-level `manage.py deploy call`, so we can call
+# `deploy` with our own set of plugin-specific CLI args.
+pytestmark = pytest.mark.skip_auto_dsd_call
+
+
+# def test_vm_size_arg(tmp_project, request):
+#     """Test that a custom vm size is written to fly.toml."""
+#     cmd = "python manage.py deploy --vm-size shared-cpu-2x"
+#     msp.call_deploy(tmp_project, cmd, platform="fly_io")
+
+#     path = tmp_project / "fly.toml"
+#     contents_fly_toml = path.read_text()
+
+#     assert 'size = "shared-cpu-2x"' in contents_fly_toml
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_help_output.py b/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_help_output.py
new file mode 100644
index 0000000..e6a68fa
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_help_output.py
@@ -0,0 +1,35 @@
+"""Test the help output when dsd-newfly is installed.
+
+The core django-simple-deploy library tests its own help output.
+This test checks that plugin-specific options are included in the help output.
+"""
+
+from pathlib import Path
+
+import pytest
+
+from tests.integration_tests.conftest import tmp_project
+from tests.integration_tests.utils import manage_sample_project as msp
+
+# Skip the default module-level `manage.py deploy call`, so we can call
+# `deploy` with our own set of plugin-specific CLI args.
+pytestmark = pytest.mark.skip_auto_dsd_call
+
+
+# def test_plugin_help_output(tmp_project, request):
+#     """Test that dsd-newfly CLI args are included in help output.
+
+#     Note: When updating this, run `manage.py deploy --help` in a terminal set
+#     to 80 characters wide. That splits help text at the same places as the 
+#     test environment.
+#     On macOS, you can simply run:
+#         $ COLUMNS=80 python manage.py deploy --help
+#     """
+#     cmd = "python manage.py deploy --help"
+#     stdout, stderr = msp.call_deploy(tmp_project, cmd)
+
+#     path_reference = Path(__file__).parent / "reference_files" / "plugin_help_text.txt"
+#     help_lines = path_reference.read_text().splitlines()
+
+#     for line in help_lines:
+#         assert line in stdout
diff --git a/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_newfly_config.py b/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_newfly_config.py
index b1e6c3a..11cec1e 100644
--- a/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_newfly_config.py
+++ b/tests/integration_tests/reference_files/dsd-newfly-no-space/tests/integration_tests/test_newfly_config.py
@@ -1,4 +1,4 @@
-"""Integration tests for django-simple-deploy, targeting Fly.io."""
+"""Integration tests for django-simple-deploy, targeting NewFly."""
 
 import sys
 from pathlib import Path

From 9d3e0b7aafd298ca1da7d22df1e96acdce665be9 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 14:24:24 -0400
Subject: [PATCH 19/21] All integration test reference files updated, all
 integration tests pass.

---
 .../dsd_greenhost_advanced/cli.py             | 63 +++++++++++++++++++
 .../dsd_greenhost_advanced/deploy.py          | 16 ++++-
 .../platform_deployer.py                      |  1 +
 .../dsd_greenhost_advanced/plugin_config.py   |  5 ++
 .../plugin_help_text_sample.txt               |  6 ++
 .../integration_tests/test_custom_cli_arg.py  | 22 +++++++
 .../test_greatgreenhost_config.py             |  2 +-
 .../integration_tests/test_help_output.py     | 35 +++++++++++
 .../dsd-newfly-single-space/dsd_newfly/cli.py | 63 +++++++++++++++++++
 .../dsd_newfly/deploy.py                      | 16 ++++-
 .../dsd_newfly/platform_deployer.py           |  1 +
 .../dsd_newfly/plugin_config.py               |  5 ++
 .../plugin_help_text_sample.txt               |  6 ++
 .../integration_tests/test_custom_cli_arg.py  | 22 +++++++
 .../integration_tests/test_help_output.py     | 35 +++++++++++
 .../integration_tests/test_newfly_config.py   |  2 +-
 16 files changed, 294 insertions(+), 6 deletions(-)
 create mode 100644 tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/cli.py
 create mode 100644 tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/reference_files/plugin_help_text_sample.txt
 create mode 100644 tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_custom_cli_arg.py
 create mode 100644 tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_help_output.py
 create mode 100644 tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/cli.py
 create mode 100644 tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/reference_files/plugin_help_text_sample.txt
 create mode 100644 tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_custom_cli_arg.py
 create mode 100644 tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_help_output.py

diff --git a/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/cli.py b/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/cli.py
new file mode 100644
index 0000000..684c855
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/cli.py
@@ -0,0 +1,63 @@
+"""Extends the core django-simple-deploy CLI."""
+
+import json
+import shlex
+import subprocess
+
+from django_simple_deploy.management.commands.utils.plugin_utils import dsd_config
+from django_simple_deploy.management.commands.utils.command_errors import (
+    DSDCommandError,
+)
+
+from .plugin_config import plugin_config
+
+
+class PluginCLI:
+
+    def __init__(self, parser):
+        """Add plugin-specific args."""
+        group_desc = "Plugin-specific CLI args for dsd-greenhost-advanced"
+        plugin_group = parser.add_argument_group(
+            title="Options for dsd-greenhost-advanced",
+            description = group_desc,
+        )
+
+        # plugin_group.add_argument(
+        #     "--vm-size",
+        #     type=str,
+        #     help="Name for a preset vm-size configuration, ie `shared-cpu-2x`.",
+        #     default="",
+        # )
+
+
+def validate_cli(options):
+    """Validate options that were passed to CLI."""
+
+    # vm_size = options["vm_size"]
+    # _validate_vm_size(vm_size)
+
+    pass
+
+
+# --- Helper functions ---
+
+# def _validate_vm_size(vm_size):
+#     """Validate the vm size arg that was passed."""
+#     if not vm_size:
+#         return
+
+#     if not dsd_config.unit_testing:
+#         cmd = "fly platform vm-sizes --json"
+#         cmd_parts = shlex.split(cmd)
+#         output = subprocess.run(cmd_parts, capture_output=True)
+#         allowed_sizes = list(json.loads(output.stdout).keys())
+#     else:
+#         allowed_sizes = ["shared-cup-1x", "shared-cpu-2x"]
+
+#     if vm_size not in allowed_sizes:
+#         msg = f"The vm-size {vm_size} requested is not available."
+#         msg += f"\n  Allowed sizes: {' '.join(allowed_sizes)}"
+#         raise DSDCommandError(msg)
+
+#     # vm_size is valid. Set the relevant plugin_config attribute.
+#     plugin_config.vm_size = vm_size
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/deploy.py b/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/deploy.py
index 21a537a..0ec8d6f 100644
--- a/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/deploy.py
+++ b/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/deploy.py
@@ -7,16 +7,28 @@
 import django_simple_deploy
 
 from dsd_greenhost_advanced.platform_deployer import PlatformDeployer
-from .plugin_config import PluginConfig
+from .plugin_config import plugin_config
+from .cli import PluginCLI, validate_cli
 
 
 @django_simple_deploy.hookimpl
 def dsd_get_plugin_config():
     """Get platform-specific attributes needed by core."""
-    plugin_config = PluginConfig()
     return plugin_config
 
 
+@django_simple_deploy.hookimpl
+def dsd_get_plugin_cli(parser):
+    """Get plugin's CLI extension."""
+    plugin_cli = PluginCLI(parser)
+
+
+@django_simple_deploy.hookimpl
+def dsd_validate_cli(options):
+    """Validate and parse plugin-specific CLI args."""
+    validate_cli(options)
+
+
 @django_simple_deploy.hookimpl
 def dsd_deploy():
     """Carry out platform-specific deployment steps."""
diff --git a/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/platform_deployer.py b/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/platform_deployer.py
index e1efc21..24f29cf 100644
--- a/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/platform_deployer.py
+++ b/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/platform_deployer.py
@@ -51,6 +51,7 @@ def _add_requirements(self):
 import requests
 
 from . import deploy_messages as platform_msgs
+from .plugin_config import plugin_config
 
 from django_simple_deploy.management.commands.utils import plugin_utils
 from django_simple_deploy.management.commands.utils.plugin_utils import dsd_config
diff --git a/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/plugin_config.py b/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/plugin_config.py
index 9c6fdcc..45e0f7e 100644
--- a/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/plugin_config.py
+++ b/tests/integration_tests/reference_files/dsd-greenhost-advanced/dsd_greenhost_advanced/plugin_config.py
@@ -25,3 +25,8 @@ def __init__(self):
         self.automate_all_supported = True
         self.confirm_automate_all_msg = platform_msgs.confirm_automate_all
         self.platform_name = "Great Green Host"
+
+
+# Create plugin_config once right here. This approach keeps from having to pass the config
+# instance between core, plugins, and these utility functions.
+plugin_config = PluginConfig()
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/reference_files/plugin_help_text_sample.txt b/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/reference_files/plugin_help_text_sample.txt
new file mode 100644
index 0000000..ef17f9c
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/reference_files/plugin_help_text_sample.txt
@@ -0,0 +1,6 @@
+Options for dsd-flyio:
+  Full documentation: https://django-simple-deploy.readthedocs.io/en/latest/
+  quick_starts/quick_start_flyio/#customizing-the-deployment
+
+  --vm-size VM_SIZE     Name for a preset vm-size configuration on Fly.io, ie
+                        `shared-cpu-2x`.
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_custom_cli_arg.py b/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_custom_cli_arg.py
new file mode 100644
index 0000000..c1fcae9
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_custom_cli_arg.py
@@ -0,0 +1,22 @@
+"""Test a custom plugin-specific CLI arg.
+"""
+
+import pytest
+
+from tests.integration_tests.conftest import tmp_project
+from tests.integration_tests.utils import manage_sample_project as msp
+
+# Skip the default module-level `manage.py deploy call`, so we can call
+# `deploy` with our own set of plugin-specific CLI args.
+pytestmark = pytest.mark.skip_auto_dsd_call
+
+
+# def test_vm_size_arg(tmp_project, request):
+#     """Test that a custom vm size is written to fly.toml."""
+#     cmd = "python manage.py deploy --vm-size shared-cpu-2x"
+#     msp.call_deploy(tmp_project, cmd, platform="fly_io")
+
+#     path = tmp_project / "fly.toml"
+#     contents_fly_toml = path.read_text()
+
+#     assert 'size = "shared-cpu-2x"' in contents_fly_toml
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_greatgreenhost_config.py b/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_greatgreenhost_config.py
index 128f4a6..4d446e6 100644
--- a/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_greatgreenhost_config.py
+++ b/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_greatgreenhost_config.py
@@ -1,4 +1,4 @@
-"""Integration tests for django-simple-deploy, targeting Fly.io."""
+"""Integration tests for django-simple-deploy, targeting Great Green Host."""
 
 import sys
 from pathlib import Path
diff --git a/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_help_output.py b/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_help_output.py
new file mode 100644
index 0000000..9e0e338
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-greenhost-advanced/tests/integration_tests/test_help_output.py
@@ -0,0 +1,35 @@
+"""Test the help output when dsd-greenhost-advanced is installed.
+
+The core django-simple-deploy library tests its own help output.
+This test checks that plugin-specific options are included in the help output.
+"""
+
+from pathlib import Path
+
+import pytest
+
+from tests.integration_tests.conftest import tmp_project
+from tests.integration_tests.utils import manage_sample_project as msp
+
+# Skip the default module-level `manage.py deploy call`, so we can call
+# `deploy` with our own set of plugin-specific CLI args.
+pytestmark = pytest.mark.skip_auto_dsd_call
+
+
+# def test_plugin_help_output(tmp_project, request):
+#     """Test that dsd-greenhost-advanced CLI args are included in help output.
+
+#     Note: When updating this, run `manage.py deploy --help` in a terminal set
+#     to 80 characters wide. That splits help text at the same places as the 
+#     test environment.
+#     On macOS, you can simply run:
+#         $ COLUMNS=80 python manage.py deploy --help
+#     """
+#     cmd = "python manage.py deploy --help"
+#     stdout, stderr = msp.call_deploy(tmp_project, cmd)
+
+#     path_reference = Path(__file__).parent / "reference_files" / "plugin_help_text.txt"
+#     help_lines = path_reference.read_text().splitlines()
+
+#     for line in help_lines:
+#         assert line in stdout
diff --git a/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/cli.py b/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/cli.py
new file mode 100644
index 0000000..a438a9a
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/cli.py
@@ -0,0 +1,63 @@
+"""Extends the core django-simple-deploy CLI."""
+
+import json
+import shlex
+import subprocess
+
+from django_simple_deploy.management.commands.utils.plugin_utils import dsd_config
+from django_simple_deploy.management.commands.utils.command_errors import (
+    DSDCommandError,
+)
+
+from .plugin_config import plugin_config
+
+
+class PluginCLI:
+
+    def __init__(self, parser):
+        """Add plugin-specific args."""
+        group_desc = "Plugin-specific CLI args for dsd-newfly"
+        plugin_group = parser.add_argument_group(
+            title="Options for dsd-newfly",
+            description = group_desc,
+        )
+
+        # plugin_group.add_argument(
+        #     "--vm-size",
+        #     type=str,
+        #     help="Name for a preset vm-size configuration, ie `shared-cpu-2x`.",
+        #     default="",
+        # )
+
+
+def validate_cli(options):
+    """Validate options that were passed to CLI."""
+
+    # vm_size = options["vm_size"]
+    # _validate_vm_size(vm_size)
+
+    pass
+
+
+# --- Helper functions ---
+
+# def _validate_vm_size(vm_size):
+#     """Validate the vm size arg that was passed."""
+#     if not vm_size:
+#         return
+
+#     if not dsd_config.unit_testing:
+#         cmd = "fly platform vm-sizes --json"
+#         cmd_parts = shlex.split(cmd)
+#         output = subprocess.run(cmd_parts, capture_output=True)
+#         allowed_sizes = list(json.loads(output.stdout).keys())
+#     else:
+#         allowed_sizes = ["shared-cup-1x", "shared-cpu-2x"]
+
+#     if vm_size not in allowed_sizes:
+#         msg = f"The vm-size {vm_size} requested is not available."
+#         msg += f"\n  Allowed sizes: {' '.join(allowed_sizes)}"
+#         raise DSDCommandError(msg)
+
+#     # vm_size is valid. Set the relevant plugin_config attribute.
+#     plugin_config.vm_size = vm_size
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/deploy.py b/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/deploy.py
index 9510dd1..7281ab2 100644
--- a/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/deploy.py
+++ b/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/deploy.py
@@ -7,16 +7,28 @@
 import django_simple_deploy
 
 from dsd_newfly.platform_deployer import PlatformDeployer
-from .plugin_config import PluginConfig
+from .plugin_config import plugin_config
+from .cli import PluginCLI, validate_cli
 
 
 @django_simple_deploy.hookimpl
 def dsd_get_plugin_config():
     """Get platform-specific attributes needed by core."""
-    plugin_config = PluginConfig()
     return plugin_config
 
 
+@django_simple_deploy.hookimpl
+def dsd_get_plugin_cli(parser):
+    """Get plugin's CLI extension."""
+    plugin_cli = PluginCLI(parser)
+
+
+@django_simple_deploy.hookimpl
+def dsd_validate_cli(options):
+    """Validate and parse plugin-specific CLI args."""
+    validate_cli(options)
+
+
 @django_simple_deploy.hookimpl
 def dsd_deploy():
     """Carry out platform-specific deployment steps."""
diff --git a/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/platform_deployer.py b/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/platform_deployer.py
index e431022..081dcb9 100644
--- a/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/platform_deployer.py
+++ b/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/platform_deployer.py
@@ -51,6 +51,7 @@ def _add_requirements(self):
 import requests
 
 from . import deploy_messages as platform_msgs
+from .plugin_config import plugin_config
 
 from django_simple_deploy.management.commands.utils import plugin_utils
 from django_simple_deploy.management.commands.utils.plugin_utils import dsd_config
diff --git a/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/plugin_config.py b/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/plugin_config.py
index a6a14b7..6977f96 100644
--- a/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/plugin_config.py
+++ b/tests/integration_tests/reference_files/dsd-newfly-single-space/dsd_newfly/plugin_config.py
@@ -25,3 +25,8 @@ def __init__(self):
         self.automate_all_supported = True
         self.confirm_automate_all_msg = platform_msgs.confirm_automate_all
         self.platform_name = "New Fly"
+
+
+# Create plugin_config once right here. This approach keeps from having to pass the config
+# instance between core, plugins, and these utility functions.
+plugin_config = PluginConfig()
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/reference_files/plugin_help_text_sample.txt b/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/reference_files/plugin_help_text_sample.txt
new file mode 100644
index 0000000..ef17f9c
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/reference_files/plugin_help_text_sample.txt
@@ -0,0 +1,6 @@
+Options for dsd-flyio:
+  Full documentation: https://django-simple-deploy.readthedocs.io/en/latest/
+  quick_starts/quick_start_flyio/#customizing-the-deployment
+
+  --vm-size VM_SIZE     Name for a preset vm-size configuration on Fly.io, ie
+                        `shared-cpu-2x`.
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_custom_cli_arg.py b/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_custom_cli_arg.py
new file mode 100644
index 0000000..c1fcae9
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_custom_cli_arg.py
@@ -0,0 +1,22 @@
+"""Test a custom plugin-specific CLI arg.
+"""
+
+import pytest
+
+from tests.integration_tests.conftest import tmp_project
+from tests.integration_tests.utils import manage_sample_project as msp
+
+# Skip the default module-level `manage.py deploy call`, so we can call
+# `deploy` with our own set of plugin-specific CLI args.
+pytestmark = pytest.mark.skip_auto_dsd_call
+
+
+# def test_vm_size_arg(tmp_project, request):
+#     """Test that a custom vm size is written to fly.toml."""
+#     cmd = "python manage.py deploy --vm-size shared-cpu-2x"
+#     msp.call_deploy(tmp_project, cmd, platform="fly_io")
+
+#     path = tmp_project / "fly.toml"
+#     contents_fly_toml = path.read_text()
+
+#     assert 'size = "shared-cpu-2x"' in contents_fly_toml
\ No newline at end of file
diff --git a/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_help_output.py b/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_help_output.py
new file mode 100644
index 0000000..e6a68fa
--- /dev/null
+++ b/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_help_output.py
@@ -0,0 +1,35 @@
+"""Test the help output when dsd-newfly is installed.
+
+The core django-simple-deploy library tests its own help output.
+This test checks that plugin-specific options are included in the help output.
+"""
+
+from pathlib import Path
+
+import pytest
+
+from tests.integration_tests.conftest import tmp_project
+from tests.integration_tests.utils import manage_sample_project as msp
+
+# Skip the default module-level `manage.py deploy call`, so we can call
+# `deploy` with our own set of plugin-specific CLI args.
+pytestmark = pytest.mark.skip_auto_dsd_call
+
+
+# def test_plugin_help_output(tmp_project, request):
+#     """Test that dsd-newfly CLI args are included in help output.
+
+#     Note: When updating this, run `manage.py deploy --help` in a terminal set
+#     to 80 characters wide. That splits help text at the same places as the 
+#     test environment.
+#     On macOS, you can simply run:
+#         $ COLUMNS=80 python manage.py deploy --help
+#     """
+#     cmd = "python manage.py deploy --help"
+#     stdout, stderr = msp.call_deploy(tmp_project, cmd)
+
+#     path_reference = Path(__file__).parent / "reference_files" / "plugin_help_text.txt"
+#     help_lines = path_reference.read_text().splitlines()
+
+#     for line in help_lines:
+#         assert line in stdout
diff --git a/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_newfly_config.py b/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_newfly_config.py
index 3ce024a..a9dbebc 100644
--- a/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_newfly_config.py
+++ b/tests/integration_tests/reference_files/dsd-newfly-single-space/tests/integration_tests/test_newfly_config.py
@@ -1,4 +1,4 @@
-"""Integration tests for django-simple-deploy, targeting Fly.io."""
+"""Integration tests for django-simple-deploy, targeting New Fly."""
 
 import sys
 from pathlib import Path

From e88d6c19f3d957ce3023b3c88e3614e9c9fb0026 Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 14:30:54 -0400
Subject: [PATCH 20/21] Update doc of generated project structure.

---
 docs/plugin_structure.md | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/docs/plugin_structure.md b/docs/plugin_structure.md
index 221abee..bfd177b 100644
--- a/docs/plugin_structure.md
+++ b/docs/plugin_structure.md
@@ -34,6 +34,7 @@ dsd-greenhost-high-traffic
 │   └── README.md
 ├── dsd_greenhost_high_traffic
 │   ├── __init__.py
+│   ├── cli.py
 │   ├── deploy.py
 │   ├── deploy_messages.py
 │   ├── platform_deployer.py
@@ -50,9 +51,11 @@ dsd-greenhost-high-traffic
     │   └── utils.py
     └── integration_tests
         ├── reference_files
-        └── test_greenhost_config.py
+        ├── test_custom_cli_arg.py
+        ├── test_greenhost_config.py
+        └── test_help_output.py
 
-8 directories, 18 files
+8 directories, 21 files
 ```
 
 Notes

From c43ae5c2607ca0dc0ad041a1b97cc79cc81d041b Mon Sep 17 00:00:00 2001
From: Eric Matthes <ehmatthes@gmail.com>
Date: Sun, 21 Sep 2025 14:35:28 -0400
Subject: [PATCH 21/21] Document changes to e2e test suite.

---
 docs/e2e_tests.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/docs/e2e_tests.md b/docs/e2e_tests.md
index 1e14597..05c45a2 100644
--- a/docs/e2e_tests.md
+++ b/docs/e2e_tests.md
@@ -75,3 +75,10 @@ test_newplatform_config.py ..................    [100%]
 This is really helpful for maintaining the test suite, and for development work.
 
 **Note:** This can get a little flaky, because we're working in a temp environment that pytest will destroy when more resources are created. If you want to keep working with these resources, you can copy the entire `e2e_new_plugin_test0` directory to a more stable location. You'll have to rebuild the `django-simple-deploy/.venv` environment, but you'll have a useful, stable development environment to work with. You'll be able to run any tests you want from that environment.
+
+Testing custom plugin CLI args
+---
+
+A plugin can extend the core django-simple-deploy CLI by defining its own custom CLI args. The code for doing this is included in the generated plugin, but code that would actually define a custom CLI arg is commented out.
+
+The e2e test suite for this plugin generator includes `e2e_tests/test_plugin_cli.py`. This test uncomments the relevant code from a generated plugin. It inserts a block of code that uses the custom CLI arg in a `deploy` call, and asserts that the expected custom behavior works successfully. It also tests that `manage.py deploy --help` includes output documenting usage of the custom CLI arg.