Building an API testing framework using RestAssured and TestNG with data-driven testing

Below are the detailed outline and sample code for building an API testing framework using RestAssured and TestNG with data-driven testing-

Project Structure

`

api-testing-framework/

│

├── src/main/java/

│   └── utils/

│       └── ExcelUtils.java

│

├── src/test/java/

│   ├── base/

│   │   └── BaseTest.java

│   │

│   ├── testcases/

│   │   └── ApiTest.java

│   │

│   ├── testdata/

│   │   └── TestData.xlsx

│   │

│   ├── resources/

│   │   └── config.properties

│   │

│   └── testng.xml

│

├── pom.xml

└── README.md

`

 Step 1: Add Dependencies in `pom.xml`

Ensure your `pom.xml` has the necessary dependencies for RestAssured, TestNG, and Apache POI (for Excel data handling).

`xml

<dependencies>

    <!-- RestAssured Dependency -->

    <dependency>

        <groupId>io.rest-assured</groupId>

        <artifactId>rest-assured</artifactId>

        <version>5.3.0</version>

    </dependency>

    <!-- TestNG Dependency -->

    <dependency>

        <groupId>org.testng</groupId>

        <artifactId>testng</artifactId>

        <version>7.7.1</version>

        <scope>test</scope>

    </dependency>

    <!-- Apache POI for Excel -->

    <dependency>

        <groupId>org.apache.poi</groupId>

        <artifactId>poi-ooxml</artifactId>

        <version>5.2.3</version>

    </dependency>

</dependencies>

`

 Step 2: Create `BaseTest.java`

This class will set up the basic configuration for RestAssured and handle common setup or teardown tasks.

`java

package base;

import io.restassured.RestAssured;

import org.testng.annotations.BeforeClass;

import java.io.FileInputStream;

import java.io.IOException;

import java.util.Properties;

public class BaseTest {

    protected Properties config = new Properties();

    @BeforeClass

    public void setUp() {

        loadConfig();

        RestAssured.baseURI = config.getProperty("baseURI");

    }

    private void loadConfig() {

        try (FileInputStream fis = new FileInputStream("src/test/resources/config.properties")) {

            config.load(fis);

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

}

`

 Step 3: Create `ExcelUtils.java`

This utility class will handle reading data from Excel files.

`java

package utils;

import org.apache.poi.ss.usermodel.*;

import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.FileInputStream;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

public class ExcelUtils {

    public static List<Object[]> getTestData(String sheetName) {

        List<Object[]> data = new ArrayList<>();

        try (FileInputStream fis = new FileInputStream("src/test/testdata/TestData.xlsx");

             Workbook workbook = new XSSFWorkbook(fis)) {

            Sheet sheet = workbook.getSheet(sheetName);

            int rows = sheet.getPhysicalNumberOfRows();

            for (int i = 1; i < rows; i++) {

                Row row = sheet.getRow(i);

                int cols = row.getPhysicalNumberOfCells();

                Object[] rowData = new Object[cols];

                for (int j = 0; j < cols; j++) {

                    rowData[j] = getCellValue(row.getCell(j));

                }

                data.add(rowData);

            }

        } catch (IOException e) {

            e.printStackTrace();

        }

        return data;

    }

    private static Object getCellValue(Cell cell) {

        switch (cell.getCellType()) {

            case STRING:

                return cell.getStringCellValue();

            case NUMERIC:

                return cell.getNumericCellValue();

            case BOOLEAN:

                return cell.getBooleanCellValue();

            default:

                return null;

        }

    }

}

`

 Step 4: Create `ApiTest.java`

This class will contain the actual test cases. It uses data from the Excel sheet to drive the tests.

`java

package testcases;

import base.BaseTest;

import io.restassured.response.Response;

import io.restassured.specification.RequestSpecification;

import org.testng.Assert;

import org.testng.annotations.DataProvider;

import org.testng.annotations.Test;

import utils.ExcelUtils;

import java.util.List;

import static io.restassured.RestAssured.given;

public class ApiTest extends BaseTest {

    @DataProvider(name = "apiData")

    public Object[][] getApiData() {

        List<Object[]> testData = ExcelUtils.getTestData("Sheet1");

        return testData.toArray(new Object[0][0]);

    }

    @Test(dataProvider = "apiData")

    public void testApi(String endpoint, String method, String requestBody, double expectedStatusCode) {

        RequestSpecification request = given();

        if (!requestBody.isEmpty()) {

            request.body(requestBody);

        }

        Response response;

        switch (method.toUpperCase()) {

            case "POST":

                response = request.post(endpoint);

                break;

            case "PUT":

                response = request.put(endpoint);

                break;

            case "DELETE":

                response = request.delete(endpoint);

                break;

            default:

                response = request.get(endpoint);

                break;

        }

        Assert.assertEquals(response.getStatusCode(), (int) expectedStatusCode);

    }

}

`

 Step 5: Create `testng.xml`

This configuration file will define how the tests should be run.

`xml

<!DOCTYPE suite SYSTEM "https://testng.org/testng-1.0.dtd">

<suite name="API Test Suite">

    <test name="API Tests">

        <classes>

            <class name="testcases.ApiTest"/>

        </classes>

    </test>

</suite>

`

 Step 6: Create `config.properties`

This file will store the base URI and other configuration details.

`

baseURI=https://api.example.com

`

 Step 7: Sample Excel Data

Create an Excel file (`TestData.xlsx`) with a sheet named `Sheet1` to store your test data.

| Endpoint         | Method | RequestBody            | ExpectedStatusCode |

|------------------|--------|------------------------|--------------------|

| /users           | GET    |                        | 200                |

| /users/1         | GET    |                        | 200                |

| /users           | POST   | {"name":"John Doe"}    | 201                |

| /users/1         | PUT    | {"name":"Jane Doe"}    | 200                |

| /users/1         | DELETE |                        | 204                |

 Step 8: Running the Tests

You can run the tests using TestNG from your IDE or from the command line.