Public `dotflow.testing` package with pytest fixtures

[FernandoCelmer]

Labels: enhancement, good first issue

Context

There is no public test harness for consumers. Anyone testing a workflow must either:

• Mock StorageDefault, ServerDefault, MetricsDefault,
  LogDefault by hand.
• Or rely on the real defaults, which is fine in unit tests but
  surfaces friction when one of them does I/O.

Concept

Expose a dotflow.testing module with ready-made fixtures. Consumers import them in their conftest.py with one line.

Proposed module

# dotflow/testing/__init__.py
import pytest
from dotflow import DotFlow, Config
from dotflow.providers.storage_default import StorageDefault

@pytest.fixture
def dotflow_storage():
    """Fresh in-memory storage for each test."""
    return StorageDefault()

@pytest.fixture
def dotflow_config(dotflow_storage):
    return Config(storage=dotflow_storage)

@pytest.fixture
def dotflow_workflow(dotflow_config):
    """A clean DotFlow with in-memory storage and no managed server."""
    return DotFlow(config=dotflow_config)

Usage in consumer code:

# user's conftest.py
from dotflow.testing import (
    dotflow_storage,
    dotflow_config,
    dotflow_workflow,
)

# user's test
def test_etl(dotflow_workflow, dotflow_storage):
    dotflow_workflow.task.add(step=extract)
    dotflow_workflow.task.add(step=transform)
    dotflow_workflow.start()
    assert dotflow_storage.get(...) is not None

Acceptance criteria

• dotflow.testing importable
• Fixtures dotflow_storage, dotflow_config,
  dotflow_workflow
• Documentation page "Testing your workflows" with usage example
• No pytest runtime dependency on the main library install
  (move to extras_require={'testing': ['pytest']})

Future expansions

• freeze_time style helper for task.duration.
• Recorder fixture that captures StatusChanged events from the bus
  introduced in this batch's issue 📘 DOCS-#6: Initial documentation #7.

[guptapiyush16]

I would like to work on it, please assign it to me

[FernandoCelmer]

I would like to work on it, please assign it to me

Welcome @guptapiyush16! Assigned to you. 😃

A few tips to get started:

• Branch from develop → feature/295
• The dotflow/testing/ directory already exists with StorageContract (added in ⚙️ FEATURE-#287: Expand Storage ABC with delete, list, TTL, CAS #297) — you'll add
  the pytest fixtures there
• Keep pytest as an optional dependency (in extras_require)
• Follow the acceptance criteria described above in the issue

Feel free to open a draft PR early for feedback. Any questions, just ask here!