Java ve Rest Assured ile API Testing

1. Giriş

API Nedir?

API (Application Programming Interface), iki uygulama arasında veri alışverişi yapılmasını sağlayan arayüzdür.
REST API ise HTTP protokolü kullanarak kaynak tabanlı veri transferi sağlar.

Rest Assured Nedir?

Rest Assured, Java tabanlı bir test kütüphanesidir ve RESTful API’lerin test edilmesini kolaylaştırır.
JUnit veya TestNG frameworkleri ile entegre çalışabilir.

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2. Test Ortamı ve Gereksinimler

Gereksinim	Açıklama
Dil	Java 8+
Kütüphane	Rest Assured
Test Framework	TestNG veya JUnit
Build Tool	Maven veya Gradle
Base URL	https://reqres.in/api

Maven Dependency

<dependency>
    <groupId>io.rest-assured</groupId>
    <artifactId>rest-assured</artifactId>
    <version>5.4.0</version>
    <scope>test</scope>
</dependency>

<dependency>
    <groupId>org.testng</groupId>
    <artifactId>testng</artifactId>
    <version>7.10.0</version>
    <scope>test</scope>
</dependency>

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3. Basit Rest Assured Testi

import io.restassured.RestAssured;
import io.restassured.response.Response;
import org.testng.annotations.Test;
import static org.hamcrest.Matchers.*;

public class GetUsersTest {

    @Test
    public void getUsers() {
        RestAssured.baseURI = "https://reqres.in/api";

        Response response = RestAssured
            .given()
                .when()
                .get("/users?page=2")
                .then()
                .statusCode(200)
                .body("data", not(empty()))
                .extract().response();

        System.out.println("Response Body: " + response.asPrettyString());
    }
}

✅ Açıklama:

• baseURI: API’nin temel adresidir.
• given() → test ön koşullarını belirtir.
• when() → HTTP isteğini gönderir.
• then() → sonuç doğrulaması yapılır.

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4. POST – Yeni Kullanıcı Oluşturma

import io.restassured.http.ContentType;
import org.testng.annotations.Test;
import static io.restassured.RestAssured.*;

public class PostUserTest {

    @Test
    public void createUser() {
        String requestBody = "{ "name": "Mehmet", "job": "QA Engineer" }";

        given()
            .baseUri("https://reqres.in/api")
            .contentType(ContentType.JSON)
            .body(requestBody)
        .when()
            .post("/users")
        .then()
            .statusCode(201)
            .body("name", equalTo("Mehmet"))
            .body("job", equalTo("QA Engineer"))
            .log().all();
    }
}

✅ Notlar:

• contentType(ContentType.JSON) → Gönderilen verinin türünü belirtir.
• log().all() → isteği ve cevabı konsola yazdırır.

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5. PUT – Kullanıcı Güncelleme

import static io.restassured.RestAssured.*;
import org.testng.annotations.Test;

public class PutUserTest {

    @Test
    public void updateUser() {
        String requestBody = "{ "name": "Mehmet", "job": "Senior QA" }";

        given()
            .baseUri("https://reqres.in/api")
            .contentType("application/json")
            .body(requestBody)
        .when()
            .put("/users/2")
        .then()
            .statusCode(200)
            .body("job", equalTo("Senior QA"))
            .log().body();
    }
}

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6. DELETE – Kullanıcı Silme

import static io.restassured.RestAssured.*;
import org.testng.annotations.Test;

public class DeleteUserTest {

    @Test
    public void deleteUser() {
        given()
            .baseUri("https://reqres.in/api")
        .when()
            .delete("/users/2")
        .then()
            .statusCode(204)
            .log().status();
    }
}

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7. JSONPath ile Veri Doğrulama

import io.restassured.path.json.JsonPath;
import io.restassured.response.Response;
import static io.restassured.RestAssured.*;
import org.testng.annotations.Test;
import static org.testng.Assert.*;

public class JsonPathExample {

    @Test
    public void validateResponseData() {
        Response response = given()
                .baseUri("https://reqres.in/api")
        .when()
                .get("/users/2")
        .then()
                .statusCode(200)
                .extract().response();

        JsonPath json = response.jsonPath();
        String email = json.getString("data.email");
        assertTrue(email.contains("@reqres.in"));
    }
}

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8. Response Zamanı ve Header Kontrolleri

import io.restassured.response.Response;
import static io.restassured.RestAssured.*;
import org.testng.annotations.Test;

public class ResponseValidationTest {

    @Test
    public void validateResponseTimeAndHeaders() {
        Response response = given()
                .baseUri("https://reqres.in/api")
        .when()
                .get("/users?page=2");

        long responseTime = response.time();
        System.out.println("Response Time: " + responseTime + " ms");

        response.then()
                .statusCode(200)
                .header("Content-Type", "application/json; charset=utf-8");
    }
}

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9. TestNG XML ile Çalıştırma

<!DOCTYPE suite SYSTEM "https://testng.org/testng-1.0.dtd">
<suite name="API Test Suite">
  <test name="Reqres API Tests">
    <classes>
      <class name="tests.GetUsersTest"/>
      <class name="tests.PostUserTest"/>
      <class name="tests.PutUserTest"/>
      <class name="tests.DeleteUserTest"/>
    </classes>
  </test>
</suite>

Konsolda çalıştırma:

mvn test -DsuiteXmlFile=testng.xml

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10. Örnek Test Raporu

Test	Sonuç	Kod	Açıklama
GET /users	PASS	200	Veri geldi
POST /users	PASS	201	Kullanıcı oluşturuldu
PUT /users/2	PASS	200	Kullanıcı güncellendi
DELETE /users/2	PASS	204	Kullanıcı silindi

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