Does Laravel automatically load .env.testing variables when Http::fake() is active?

No. Laravel does not automatically load .env.testing variables simply because Http::fake() is active. There is no causal link between the HTTP client's mocking utility and the application's environment loading mechanism.

Understanding the Separation of Concerns

Http::fake() is a runtime utility used to intercept outbound requests. It operates at the service level to prevent real network calls from leaving the application. In contrast, environment variable loading happens during the application's bootstrap phase, long before individual test methods are executed.

How .env.testing is Actually Loaded

Laravel loads .env.testing based on the environment configuration provided to the test runner (typically PHPUnit or Pest), not based on the code within the test itself. The standard flow is as follows:

• The test runner reads phpunit.xml.
• If is defined, Laravel looks for a .env.testing file.
• If found, it loads those variables into the environment.
• The application then boots, and Http::fake() is called during the test execution phase.

Ensuring Test-Only Credentials

To guarantee that your tests do not use production keys, you must rely on the test bootstrap configuration rather than the HTTP fake. Follow these steps to verify your setup:

1. Verify phpunit.xml: Ensure your phpunit.xml file contains the environment directive:

   <php>
       <env name="APP_ENV" value="testing" />
   </php>

2. Check File Existence: Confirm that a .env.testing file exists in your project root with the correct dummy credentials.
3. Runtime Verification: To be certain which environment is active, add a temporary dump to your test method:

   public function test_api_call() {
       dump(env('APP_ENV')); // Should output 'testing'
       Http::fake();
       // ... test logic
   }

Configuration Overrides

If you need to change a specific value for a single test without changing the global .env.testing file, use the Config facade instead of relying on environment files:

config(['services.api.key' => 'test-key-123']);

Diagnostic Note: Are you running tests via a custom CI script or a non-standard test runner? If so, the APP_ENV variable may not be passed correctly, which would cause Laravel to fall back to .env.