Disable SolidAPM in test

README.md

@@ -99,6 +99,18 @@ The sampling is done per-thread using a round-robin counter, ensuring even distr
 This is useful for high-traffic applications where you want to reduce the volume of
 APM data while still maintaining representative performance insights.
 
+### Test Environment
+
+**SolidAPM is automatically disabled in the test
+environment** to prevent test pollution and improve test performance.
+
+You can disable SolidAPM in other environments if needed:
+
+```ruby
+# config/environments/staging.rb
+SolidApm.enabled = false
+```
+
 ### Transaction Name Filtering
 
 Filter specific transactions by name using exact string matches or regular expressions:

lib/solid_apm.rb

@@ -4,6 +4,7 @@
 require 'apexcharts'
 
 require 'solid_apm/version'
+require 'solid_apm/railtie'
 require 'solid_apm/engine'
 require 'solid_apm/sampler'
 require 'solid_apm/cleanup_service'
@@ -13,6 +14,7 @@ module SolidApm
   mattr_accessor :mcp_server_config, default: {}
   mattr_accessor :silence_active_record_logger, default: true
   mattr_accessor :transaction_sampling, default: 1
+  mattr_accessor :enabled, default: true
   mattr_accessor(
     :transaction_filters, default: [
       /^SolidApm::/,

lib/solid_apm/engine.rb

@@ -4,7 +4,9 @@ module SolidApm
   class Engine < ::Rails::Engine
     isolate_namespace SolidApm
 
-    config.app_middleware.use Middleware
+    initializer 'solid_apm.middleware', before: :build_middleware_stack do |app|
+      app.middleware.use SolidApm::Middleware if SolidApm.enabled
+    end
 
     initializer 'solid_apm.assets' do |app|
       # Add engine's assets to the load path for both Propshaft and Sprockets
@@ -49,7 +51,7 @@ class Engine < ::Rails::Engine
     end
 
     config.after_initialize do
-      SpanSubscriber::Base.subscribe!
+      SpanSubscriber::Base.subscribe! if SolidApm.enabled
     end
   end
 end

lib/solid_apm/middleware.rb

@@ -7,10 +7,12 @@ def initialize(app)
     end
 
     def call(env)
+      return @app.call(env) unless SolidApm.enabled
+
       self.class.init_transaction
       status, headers, body = @app.call(env)
 
-        env['rack.after_reply'] ||= []
+      env['rack.after_reply'] ||= []
         env['rack.after_reply'] << ->() do
           self.class.call
         rescue StandardError => e
@@ -25,8 +27,8 @@ def self.call
       SpanSubscriber::Base.transaction = nil
 
       if transaction.nil? ||
-          transaction_filtered?(transaction.name) ||
-          !Sampler.should_sample?
+         transaction_filtered?(transaction.name) ||
+         !Sampler.should_sample?
 
         SpanSubscriber::Base.spans = nil
         return

lib/solid_apm/railtie.rb

@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module SolidApm
+  class Railtie < Rails::Railtie
+    config.before_initialize do
+      # Always disable in test environment to prevent test pollution
+      SolidApm.enabled = false if Rails.env.test?
+    end
+  end
+end

spec/lib/solid_apm/configuration_spec.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'SolidApm configuration' do
+  describe '.enabled' do
+    it 'is disabled in test environment' do
+      # SolidAPM is always disabled in test to prevent pollution
+      expect(SolidApm.enabled).to be false
+    end
+
+    it 'can be set to false' do
+      original = SolidApm.enabled
+      SolidApm.enabled = false
+      expect(SolidApm.enabled).to be false
+      SolidApm.enabled = original
+    end
+  end
+end

spec/lib/solid_apm/railtie_spec.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe SolidApm::Railtie do
+  describe 'test environment auto-disable' do
+    it 'is disabled in test environment' do
+      # Railtie always disables in test environment
+      expect(Rails.env.test?).to be true
+      expect(SolidApm.enabled).to be false
+    end
+  end
+end

spec/services/solid_apm/middleware_spec.rb

@@ -1,6 +1,26 @@
 # frozen_string_literal: true
 
 RSpec.describe SolidApm::Middleware do
+  describe 'when disabled' do
+    around do |example|
+      original = SolidApm.enabled
+      SolidApm.enabled = false
+      example.run
+    ensure
+      SolidApm.enabled = original
+    end
+
+    it 'passes through without tracking' do
+      app = ->(_env) { [200, {}, ['OK']] }
+      middleware = described_class.new(app)
+
+      status, _headers, _body = middleware.call({})
+
+      expect(status).to eq(200)
+      expect(SolidApm::SpanSubscriber::Base.transaction).to be_nil
+    end
+  end
+
   describe '.transaction_filtered?' do
     before do
       SolidApm.transaction_filters = []
@@ -74,4 +94,4 @@
       end
     end
   end
-end
+end