Given/When/Then & Assertions

Basic Requests

import static io.restassured.RestAssured.*;
import static org.hamcrest.Matchers.*;

@BeforeAll
static void setup() {
    RestAssured.baseURI = "https://api.example.com";
}

@Test
void getUser_returnsExpectedFields() {
    given()
        .header("Authorization", "Bearer " + token)
        .queryParam("expand", "profile")
    .when()
        .get("/users/1")
    .then()
        .statusCode(200)
        .body("name", equalTo("Alice"))
        .body("email", containsString("@"))
        .header("Content-Type", containsString("application/json"));
}

POST with a Body & Extracting Values

@Test
void createUser_thenUseReturnedId() {
    String userJson = "{ \"name\": \"Bob\" }";

    int newId = given()
        .contentType(ContentType.JSON)
        .body(userJson)
    .when()
        .post("/users")
    .then()
        .statusCode(201)
        .extract().path("id");  // extract for use in a LATER request

    given()
        .when().get("/users/" + newId)
        .then().statusCode(200).body("name", equalTo("Bob"));
}

// A POJO works too — REST Assured serializes it automatically
// given().contentType(ContentType.JSON).body(new User("Bob")).post("/users");

Debugging

given()
    .log().all()          // print the full request before sending
.when()
    .get("/users/1")
.then()
    .log().ifValidationFails()  // only print response details on assertion failure
    .statusCode(200);