Skill: gen-test

Generate idiomatic tests for Go packages and handlers in the Meshery project.

Usage

Invoke this skill with a target file or package path:

• /gen-test server/handlers/provider_handler.go
• /gen-test mesheryctl/internal/cli/root/system/start.go

Instructions

1. Read the target file to understand its exported functions, methods, and types.
2. Read existing tests in the same package (look for *_test.go files) to match the project's testing style.
3. Generate tests following these conventions:

Go Test Conventions

• Use table-driven tests with t.Run subtests
• Name test functions Test<FunctionName> or Test<Type>_<Method>
• Use testify/assert or testify/require if already used in the package; otherwise use standard library
• For HTTP handlers, use httptest.NewRecorder() and httptest.NewRequest()
• Mock external dependencies using interfaces — check if mock implementations already exist in the package
• Test both success and error paths
• Include edge cases: nil inputs, empty strings, boundary values

File Placement

• Place test files in the same directory as the source file
• Name: <source_file>_test.go (or append to existing test file if one exists)

What to Test

For handlers (server/handlers/):

• HTTP status codes for valid and invalid requests
• Response body structure
• Authentication/authorization checks (if applicable)
• Input validation errors

For models (server/models/):

• Struct method behavior
• Serialization/deserialization
• Validation logic

For mesheryctl commands (mesheryctl/):

• Command output for various flag combinations
• Error messages for invalid input
• Exit codes

Example Pattern

func TestHandlerName(t *testing.T) {
    tests := []struct {
        name           string
        method         string
        path           string
        body           string
        expectedStatus int
    }{
        {
            name:           "valid request",
            method:         http.MethodGet,
            path:           "/api/resource",
            expectedStatus: http.StatusOK,
        },
        {
            name:           "missing required field",
            method:         http.MethodPost,
            path:           "/api/resource",
            body:           `{}`,
            expectedStatus: http.StatusBadRequest,
        },
    }

    for _, tt := range tests {
        t.Run(tt.name, func(t *testing.T) {
            req := httptest.NewRequest(tt.method, tt.path, strings.NewReader(tt.body))
            rec := httptest.NewRecorder()

            handler.ServeHTTP(rec, req)

            if rec.Code != tt.expectedStatus {
                t.Errorf("expected status %d, got %d", tt.expectedStatus, rec.Code)
            }
        })
    }
}