Enforce AAA test pattern and TestMethod_Scenario_ExpectedBehavior naming convention

[Copilot]

Standardizes test suite to follow AAA (Arrange-Act-Assert) pattern with explicit comment separators and adopts TestMethod_Scenario_ExpectedBehavior naming convention for all test methods.

Changes

Test naming refactored - 11 test methods renamed:

• TestGetOs() → GetOs_WhenCalled_ReturnsValidOsIdentifier()
• TestExitCodes() → Main_WithShellExitCode_ReturnsMatchingExitCode()
• TestArgumentPassing() → Main_WithShellArguments_PassesArgumentsToProgram()
• TestMissingConfigFile() → Main_WhenConfigFileMissing_ReturnsErrorWithMessage()
• TestUnsupportedTarget() → Main_WithUnsupportedTarget_ReturnsErrorWithMessage()
• TestBadConfiguration() → Main_WithBadConfiguration_ReturnsErrorWithMessage()

AAA pattern enforced - All tests restructured with explicit sections:

[TestMethod]
public void GetOs_WhenCalled_ReturnsValidOsIdentifier()
{
    // Arrange
    // No arrangement needed - testing static method with no input

    // Act
    var os = Program.GetOs();

    // Assert
    Assert.IsNotNull(os);
    Assert.IsTrue(os is "win" or "linux" or "freebsd" or "osx" or "unknown");
}

Standards documented in .globalconfig:

• AAA pattern requirement with comment separation
• TestMethod_Scenario_ExpectedBehavior naming convention
• Updated CA1707 suppression rationale to reference naming convention

Original prompt

Please review the software for appropriate quality. Additionaly it may be appropriate to mandate the AAA (Arrange-Act-Assert) test pattern, and the TestMethod_Scenario_ExpectedBehavior naming convention.

Custom agent used: Software Quality Enforcer
Code quality specialist for enforcing testing standards, static analysis, and zero-warning builds

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.