REST Assured - Quick Reference

Deep Knowledge: Use mcp__documentation__fetch_docs with technology: rest-assured for comprehensive documentation.

When NOT to Use This Skill

• Unit Tests - Use junit with Mockito for isolated tests
• E2E Browser Tests - Use Selenium or Playwright
• WebSocket Testing - Use dedicated WebSocket testing tools
• Non-Java Projects - Use language-specific HTTP clients
• GraphQL APIs - Consider GraphQL-specific testing tools

Pattern Essenziali

GET Request

given()
    .baseUri("http://localhost:8080")
    .contentType("application/json")
.when()
    .get("/api/v1/users/1")
.then()
    .statusCode(200)
    .body("name", equalTo("John"));

POST Request

given()
    .contentType("application/json")
    .body("""
        {"name": "John", "email": "john@example.com"}
        """)
.when()
    .post("/api/v1/users")
.then()
    .statusCode(201)
    .body("id", notNullValue());

Spring Boot Integration

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class UserApiTest {
    @LocalServerPort
    private int port;

    @BeforeEach
    void setUp() {
        RestAssured.port = port;
    }

    @Test
    void shouldGetUsers() {
        given()
        .when().get("/api/v1/users")
        .then().statusCode(200);
    }
}

Authentication

// Bearer Token
given().header("Authorization", "Bearer " + token)

// Basic Auth
given().auth().basic("user", "pass")

Hamcrest Matchers Comuni

| Matcher | Uso | |---------|-----| | equalTo(value) | Exact match | | notNullValue() | Not null | | hasSize(n) | Collection size | | containsString(str) | String contains |

Anti-Patterns

| Anti-Pattern | Why It's Bad | Solution | |--------------|--------------|----------| | Hardcoding base URI | Not portable across environments | Use RestAssured.baseURI or config | | Not setting contentType | Request may fail or be misinterpreted | Always set contentType for POST/PUT | | Ignoring status codes | Silent failures | Always assert status code | | Not using path parameters | Hard to read, error-prone | Use {id} placeholders | | Testing too much in one test | Hard to debug | One endpoint/scenario per test | | No authentication testing | Security gaps | Test auth headers, tokens | | Not validating response schema | API contract violations | Use JSON schema validation |

Quick Troubleshooting

| Problem | Likely Cause | Solution | |---------|--------------|----------| | "Connection refused" | Server not running | Start server, verify port | | "Expected status 200 but was 500" | API error or wrong request | Check server logs, validate request body | | "Cannot deserialize JSON" | Wrong content type or body format | Verify Content-Type header, check JSON | | Authentication fails | Missing/wrong token | Check Authorization header | | Timeout | Slow API or network issue | Increase timeout or investigate performance | | "Path not found" | Wrong URL or method | Verify endpoint exists, check HTTP method |

Reference Documentation

• REST Assured Docs