Lesson 4
Testing Authenticated Endpoints
Testing Authenticated Endpoints

Welcome to the final stage of our journey through automated API testing with Scala. In this lesson, we'll focus on testing authenticated API endpoints. While you've already learned to organize tests and handle CRUD operations using MUnit, today we'll delve into how APIs manage secure access through different authentication methods — API Keys, Sessions, and JWT (JSON Web Tokens).

Authentication is crucial for securing API endpoints against unauthorized access. By understanding how to test these mechanisms, you'll ensure that your API maintains its integrity and protects sensitive data. We'll explore practical examples for each authentication method, giving you the tools to verify that only authorized users can interact with protected resources.

API Key Authentication

API Key authentication is one of the simplest ways to secure an API. It involves sending a unique key as part of the request headers, allowing access to protected endpoints. Let's look at an example of how you can set up and test API Key authentication using Scala:

Scala
1class APIKeyAuthenticationSuite extends FunSuite:
2
3  val BASE_URL = "http://localhost:8000"
4  val API_KEY = "123e4567-e89b-12d3-a456-426614174000"
5
6  test("should authenticate successfully with valid API key"):
7    // Arrange
8    val headers = Map("X-API-Key" -> API_KEY)
9
10    // Act
11    val response = requests.get(s"$BASE_URL/todos", headers = headers)
12
13    // Assert
14    assertEquals(response.statusCode, 200)

Here, we define a test class APIKeyAuthenticationSuite. Within the test method, we specify the headers, including the X-API-Key. We use the requests.get method to make a call to the /todos endpoint and pass the headers, ensuring the API key is included in the request. The test then asserts that the response status code is 200, indicating successful authentication and access to the endpoint.

Session Authentication: Setup

We begin our session-based authentication by establishing a method for user credentials and a helper method for login. This enables each test to authenticate independently, providing a consistent environment to test both login functionality and access to protected endpoints:

Scala
1class SessionAuthenticationSuite extends FunSuite:
2
3  val BASE_URL = "http://localhost:8000"
4
5  def authDetails = 
6    // Arrange - Providing user credentials
7    Obj(
8      "username" -> Str("testuser"), 
9      "password" -> Str("testpass123")
10    )
11
12  // Helper method for sending a login POST request
13  def login(session: requests.Session, authDetails: Obj): Response = 
14    // Sends a login request and maintains session state
15    session.post(s"$BASE_URL/auth/login", data = authDetails)

The authDetails method supplies the required credentials, and the login helper method facilitates independent authentication for each test.

Session Authentication: Testing Login

This test leverages the login helper method to authenticate independently, validating that user credentials create a session successfully:

Scala
1  test("should successfully log in with valid credentials"):
2    // Arrange - Initialize session
3    val session = Session()
4
5    // Act - Execute the login process using the helper method
6    val loginResponse = login(session, authDetails)
7
8    // Assert - Verify that the login was successful
9    assertEquals(loginResponse.statusCode, 200)

The use of the helper ensures that this test does not rely on any previous operations, providing isolated verification of login success via status code.

Session Authentication: Testing Protected Endpoint

In this test, we independently authenticate using the helper method before confirming that an established session grants access to a protected endpoint:

Scala
1  test("should access protected endpoint with valid session"):
2    // Arrange - Use the login helper method to authenticate
3    val session = Session()
4    login(session, authDetails)
5
6    // Act - Request the protected resource using the session
7    val response = session.get(s"$BASE_URL/todos")
8
9    // Assert - Confirm access is granted with a successful status code
10    assertEquals(response.statusCode, 200)

The helper method's strategic use ensures that each test individually verifies session-based access, unaffected by the results of prior tests.

Session Authentication: Testing Logout

By using the login helper method, this test independently authenticates and then verifies the ability to terminate a session, ensuring logout functionality is effective:

Scala
1  test("should successfully log out and invalidate session"):
2    // Arrange - Use the login helper method to authenticate
3    val session = Session()
4    login(session, authDetails)
5
6    // Act - Perform a logout operation to terminate the session
7    val logoutResponse = session.post(s"$BASE_URL/auth/logout")
8
9    // Assert - Verify logout success via status code
10    assertEquals(logoutResponse.statusCode, 200)

This approach confirms isolation, as each session is independently managed, ensuring logout integrity without relying on previous tests.

JWT Authentication: Setup

For JWT-based authentication, we replicate this strategy with a method for credentials and a login helper method, enabling each test to independently obtain and manage JWTs:

Scala
1class JWTAuthenticationSuite extends FunSuite:
2
3  val BASE_URL = "http://localhost:8000"
4
5  def authDetails = 
6    // Arrange - User credentials for JWT
7    Obj(
8      "username" -> Str("testuser"), 
9      "password" -> Str("testpass123")
10    )
11
12  // Helper method for sending a login POST request
13  def login(authDetails: Obj): Response = 
14    // Obtain JWT tokens with login request
15    requests.post(s"$BASE_URL/auth/login", data = authDetails)

This setup empowers each test to authenticate independently, retrieving tokens without relying on the order or success of other tests.

JWT Authentication: Testing Login

Using the login helper method, this test independently verifies that successful authentication results in token issuance, forming the basis for accessing protected resources:

Scala
1  test("should receive valid JWT tokens upon successful login"):
2    // Act - Authenticate and retrieve JWT tokens
3    val loginResponse = login(authDetails)
4
5    // Assert - Confirm receipt of tokens and check their existence
6    assertEquals(loginResponse.statusCode, 200)
7    val tokens = read(loginResponse.text())
8    assert(tokens.obj.contains("access_token"))
9    assert(tokens.obj.contains("refresh_token"))

By independently logging in, the test ensures token validity regardless of prior tests, establishing the foundation for secure access.

JWT Authentication: Testing Protected Endpoint

This test independently authenticates using the helper method and verifies that a JWT access token provides entry to a protected endpoint:

Scala
1  test("should access protected endpoint with valid JWT"):
2    // Arrange - Authenticate and obtain an access token using the helper method
3    val loginResponse = login(authDetails)
4    val accessToken = read(loginResponse.text())("access_token").str
5
6    // Act - Use the access token to request a protected endpoint
7    val headers = Map("Authorization" -> s"Bearer $accessToken")
8    val response = requests.get(s"$BASE_URL/todos", headers = headers)
9
10    // Assert - Confirm the request was successful by checking the status code
11    assertEquals(response.statusCode, 200)

By ensuring the test is independent, this approach validates the token's effectiveness in protecting resources, confirming stateless authentication.

JWT Authentication: Testing Logout

Finally, this test independently authenticates to verify that access and refresh tokens can be invalidated, securing the system against unauthorized reuse:

Scala
1  test("should successfully invalidate JWT tokens on logout"):
2    // Arrange - Authenticate and prepare tokens using the helper method
3    val loginResponse = login(authDetails)
4    val accessToken = read(loginResponse.text())("access_token").str
5    val refreshToken = read(loginResponse.text())("refresh_token").str
6
7    val headers = Map("Authorization" -> s"Bearer $accessToken")
8
9    // Act - Use access and refresh tokens to process logout
10    val logoutResponse = requests.post(
11      s"$BASE_URL/auth/logout", 
12      headers = headers, 
13      data = Obj("refresh_token" -> Str(refreshToken))
14    )
15
16    // Assert - Verify logout success through confirmation of status code
17    assertEquals(logoutResponse.statusCode, 200)

This test confirms the secure handling and invalidation of tokens, ensuring each test independently checks the integrity of the logout process.

Summary and Practices

Throughout this lesson, we've explored different methods of API authentication: API Keys, Sessions, and JWTs. Each method has distinct ways to test and secure access, and you've seen how to implement tests for them effectively using Scala, MUnit, and Requests-Scala.

When testing any form of authentication, it's crucial to handle API credentials with care. Avoid hardcoding sensitive information in your codebase, and consider using environment variables or secure vaults in production environments.

As we conclude this lesson and the course, take pride in the journey you've completed. You've gained a comprehensive understanding of how to automate API tests using Scala, mastering basic requests through to secure, authenticated endpoints. Continue to practice and explore, applying these skills to ensure robust, reliable APIs in your projects. Congratulations on reaching the end of this course!

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