Testing Patterns

Go Testing Patterns

Table-Driven Tests (Standard Pattern)

func TestFunction(t *testing.T) {
    tests := []struct {
        name        string
        input       SomeType
        wantOutput  ExpectedType
        wantErr     bool
        errContains string
    }{
        {
            name:       "happy path",
            input:      SomeType{...},
            wantOutput: ExpectedType{...},
            wantErr:    false,
        },
        {
            name:        "error case",
            input:       SomeType{...},
            wantErr:     true,
            errContains: "expected error message",
        },
    }

    for _, tt := range tests {
        t.Run(tt.name, func(t *testing.T) {
            got, err := FunctionUnderTest(tt.input)

            if tt.wantErr {
                assert.Error(t, err)
                if tt.errContains != "" {
                    assert.Contains(t, err.Error(), tt.errContains)
                }
                return
            }

            assert.NoError(t, err)
            assert.Equal(t, tt.wantOutput, got)
        })
    }
}

Mockery v3.5 Usage

// Create mock with automatic cleanup
executor := mocks.NewMockForgeExecutor(t)

// Type-safe expectation setting
executor.EXPECT().Execute(
    mock.Anything,      // context
    mock.MatchedBy(func(cfg Config) bool {
        return cfg.TestFile != ""
    }),
).Return(&Result{Success: true}, nil).Once()

// AssertExpectations called automatically via t.Cleanup

Table-Driven Tests with Mocks

tests := []struct {
    name       string
    setupMocks func(*mocks.MockForgeExecutor)
    wantResult *Result
    wantErr    error
}{
    {
        name: "successful execution",
        setupMocks: func(m *mocks.MockForgeExecutor) {
            m.EXPECT().Execute(mock.Anything, mock.Anything).
                Return(&Result{Success: true}, nil).Once()
        },
        wantResult: &Result{Success: true},
    },
}

for _, tt := range tests {
    t.Run(tt.name, func(t *testing.T) {
        executor := mocks.NewMockForgeExecutor(t)
        tt.setupMocks(executor)
        // ... test logic
    })
}

Mock Commands

task mocks          # Generate all mocks (regenerates from scratch)

Test Organization

• Test behaviors, not implementation - Focus on public APIs
• Use t.Helper() for test utilities
• Coverage targets: ≥80% unit tests, ≥70% integration tests
• Run with race detector: task test-race

Security in Tests

NEVER hardcode secrets!

// WRONG
const testAPIKey = "sk-test-12345"

// RIGHT
apiKey := "test-" + generateRandomString(32)

Build Tags

All test commands require the -tags=testmode build tag:

gotestsum --format pkgname -- -tags=testmode -run TestFunctionName ./internal/hooks/...

Test Execution

task test              # Fast tests (-short, 30s timeout)
task test-race         # Tests with race detector
task coverage          # HTML coverage report

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