Second Test Fails, Wiremock Stubs Not Being Reset After Test: A Comprehensive Guide to Troubleshooting

Are you tired of dealing with flaky tests that fail unexpectedly? Do you find yourself scratching your head, trying to figure out why your Wiremock stubs aren’t being reset after each test? You’re not alone! In this article, we’ll dive deep into the common pitfalls and provide you with clear, step-by-step instructions to troubleshoot and fix the issue once and for all.

What are Wiremock Stubs?

Before we dive into the troubleshooting process, let’s take a quick step back and understand what Wiremock stubs are. Wiremock is a popular library used for mocking HTTP requests in Java-based applications. It allows you to create fake endpoints that mimic real API responses, making it an essential tool for unit testing and integration testing.

Wiremock stubs are essentially pre-defined responses to specific HTTP requests. They’re created using Wiremock’s API and can be configured to return custom responses, headers, and even error codes. In a typical testing scenario, you’d create multiple stubs to cover various test scenarios, and then reset them after each test to ensure a clean slate.

The Problem: Second Test Fails, Wiremock Stubs Not Being Reset

Now, let’s talk about the problem at hand. You’ve written a set of tests that use Wiremock stubs to mock out API requests. The first test runs successfully, but the second test fails unexpectedly, and you’ve verified that the Wiremock stubs are not being reset after the first test. This can be frustrating, especially when you’ve spent hours writing and refactoring your code.

So, what’s causing this issue?

Possible Causes

There are several reasons why Wiremock stubs might not be resetting after each test. Here are some possible causes:

• Improper Wiremock configuration
• Incorrect test setup and teardown
• Stub tampering or modification during test execution
• Inconsistent Wiremock versioning
• Conflicting test frameworks or libraries

Troubleshooting Steps

Now that we’ve identified some possible causes, let’s walk through a series of troubleshooting steps to help you resolve the issue.

Step 1: Verify Wiremock Configuration

First, make sure you’ve configured Wiremock correctly in your test setup. Check your Wiremock configuration file (usually `wiremock.json` or `wiremock.properties`) and ensure that:

• The `reset-mock` property is set to `true`
• The `record-mock` property is set to `false` (unless you’re using record-and-replay mode)
• The `stub` property is correctly configured to point to your stub definitions

{
  "record-mock": false,
  "reset-mock": true,
  "stub": {
    "mappings": [
      {
        "request": {
          "method": "GET",
          "url": "/users"
        },
        "response": {
          "status": 200,
          "body": "{\"users\": [{\"id\": 1, \"name\": \"John\"}]}"
        }
      }
    ]
  }
}

Step 2: Check Test Setup and Teardown

Next, review your test setup and teardown methods to ensure that:

• Wiremock is started and stopped properly
• Stubs are reset before each test
• No global state is being shared between tests

@BeforeEach
public void setup() {
  wireMockServer = new WireMockServer(wireMockConfig);
  wireMockServer.start();
  resetStubs();
}

@AfterEach
public void tearDown() {
  wireMockServer.stop();
}

Step 3: Identify Stub Tampering

Determine if any part of your test code is modifying or tampering with the stubs during test execution. This could be due to:

• Accidental stub modification
• Third-party libraries or dependencies
• Inconsistent stub definitions

@Test
public void myTest() {
  // Avoid modifying stubs during test execution
  stubFor(get(urlEqualTo("/users")).willReturn(aResponse().withStatus(404)));
  
  // ...
}

Step 4: Check Wiremock Versioning

Verify that you’re using the correct version of Wiremock, as different versions may have different configuration options or behaviors.

<dependency>
  <groupId>com.github.tomakehurst</groupId>
  <artifactId>wiremock</artifactId>
  <version>2.27.2</version>
</dependency>

Step 5: Investigate Conflicting Test Frameworks or Libraries

Check if other test frameworks or libraries are interfering with Wiremock’s behavior. This could be due to:

• Conflicting annotations or configuration
• Incompatible library versions
• Overlapping test setup and teardown

@ExtendWith(SpringExtension.class)
@SpringBootTest
public class MyTest {
  // ...
}

Conclusion

By following these troubleshooting steps, you should be able to identify and fix the issue causing Wiremock stubs not to reset after each test. Remember to double-check your Wiremock configuration, test setup and teardown, and identify any potential sources of stub tampering or conflicts.

Bonus Tips and Best Practices

To avoid similar issues in the future, here are some bonus tips and best practices:

Tips and Best Practices	Description
Use a separate Wiremock instance per test	Ensure each test has its own isolated Wiremock instance to prevent stub pollution.
Reset stubs before each test	Use `resetStubs()` or similar methods to clear stubs before each test.
Avoid global state and static variables	Refactor your code to avoid sharing global state or static variables between tests.
Use Wiremock’s built-in reset functionality	Take advantage of Wiremock’s built-in reset functionality to clear stubs and recordings.

By following these guidelines and troubleshooting steps, you’ll be well-equipped to handle Wiremock stubs not resetting after each test and ensure your tests run smoothly and reliably.

Happy testing!

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