REST Assured practice API: check JSON data and HTTP 418

Learn to distinguish a valid business response from an intentionally unusual HTTP status. These read-only examples do not require authentication.

Before you start

An existing Java test project with REST Assured and JUnit Jupiter configured.
Save the example in your test source folder as CoffeeApiTest.java and run your project test command.
REST Assured uses Hamcrest matchers; use compatible dependencies in your existing project.

Check a filtered JSON contract

The first test checks the status, content type and each drink type. The second expects the teapot endpoint to return HTTP 418.

import org.junit.jupiter.api.Test;
import java.util.UUID;
import static io.restassured.RestAssured.given;
import static org.hamcrest.Matchers.*;

class CoffeeApiTest {
  @Test void hotDrinksHaveTheExpectedType() {
    given().baseUri("https://funapi.dev/api")
      .header("X-Sandbox-ID", UUID.randomUUID().toString())
      .queryParam("type", "hot")
    .when().get("/coffee/v1/drinks")
    .then().statusCode(200).contentType("application/json")
      .body("data.size()", greaterThan(0))
      .body("data.type", everyItem(equalTo("hot")));
  }

  @Test void teapotStatusIsAnExpectedResult() {
    given().baseUri("https://funapi.dev/api")
      .header("X-Sandbox-ID", UUID.randomUUID().toString())
    .when().get("/coffee/v1/teapot")
    .then().statusCode(418);
  }
}

Extend the validation boundary

Add GET /coffee/v1/drinks?type=warm and expect 400. Keep this separate from the valid hot/cold cases so a failure explains which contract changed.

Expected result

The provided two tests pass: hot drinks return JSON with 200, and the teapot returns 418. The optional invalid type returns 400.

Common pitfalls

Place the class in your test source directory and ensure JUnit discovers it.
An intentional 418 should not be rewritten as a 200 expectation.
Use a fresh sandbox identifier for independent tests rather than a shared classroom value.

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Last updated 16 October 2026