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