11_httpexpect

httpexpect

httpexpect is a concise and chainable HTTP/REST API testing library for Go. It provides expressive assertions for testing HTTP handlers and APIs with minimal boilerplate.

📦 Installation

go get github.com/gavv/httpexpect/v2

🎯 Features

• Chainable API: Fluent interface for readable tests
• Rich Assertions: JSON, headers, status, cookies, etc.
• Built-in Matchers: Equal, Contains, Match (regex), etc.
• WebSocket Support: Test WebSocket connections
• FormData & Multipart: File uploads and forms
• Integration: Works with net/http handlers or live servers

📖 Usage

Basic API Test

e := httpexpect.New(t, "http://localhost:8080")

e.GET("/users/1").
    Expect().
    Status(200).
    JSON().Object().
    ValueEqual("name", "John")

Testing HTTP Handler

handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    w.WriteHeader(200)
    w.Write([]byte(`{"message": "Hello"}`))
})

e := httpexpect.WithConfig(httpexpect.Config{
    Client:   &http.Client{},
    BaseURL:  "http://example.com",
    Reporter: httpexpect.NewAssertReporter(t),
    Printers: []httpexpect.Printer{
        httpexpect.NewDebugPrinter(t, true),
    },
})

e.GET("/").WithHandler(handler).
    Expect().
    Status(200).
    JSON().Object().
    ValueEqual("message", "Hello")

🚀 Running Tests

go test
go test -v  # See HTTP requests/responses

✅ Pros

• ✅ Extremely readable test code
• ✅ Comprehensive HTTP assertions
• ✅ Works with handlers or live servers
• ✅ Excellent for API testing
• ✅ JSON path navigation
• ✅ Schema validation support

❌ Cons

• ❌ HTTP-only (not for general testing)
• ❌ Learning curve for chainable API
• ❌ Can be verbose for simple tests
• ❌ Focused on REST/JSON APIs

🔗 Resources

• GitHub Repository
• Documentation
• Examples

💡 Best Practices

1. Chain assertions: Make tests readable
2. Test handlers directly: Faster than live servers
3. Use WithHandler: For unit testing handlers
4. Validate JSON schema: Ensure API contracts
5. Check all response aspects: Status, headers, body