WireMock - Request Matching with JUnit Test

WireMock is a tool for mocking HTTP-based APIs that runs in the unit tests, on the desktop, or in the test environment. Read more about WireMock in this article: Introduction to WireMock. One of the most important features of WireMock is Request Matching. WireMock supports matching of requests to stubs and verification queries using the following attributes: URL, HTTP Method, Query parameters, Headers, Cookies, Request body, etc. So in this article, we are going to see how Request Matching works with JUnit Test in WireMock.

Prerequisites:

• Refer to this article and install WireMock on your local machine: How to Download and Install WireMock?
• How to Use WireMock with JUnit Test? 

1. URL Matching

In WireMock, the URLs can be matched either by equality or by regular expression. And you can match just the path of the URL or the path and query together. Let's see both scenarios with examples.

Example: Equality matching on the path only

Syntax:

urlPathEqualTo("/your/url")

Now let's demonstrate this with the help of IntelliJ IDEA as the IDE and Maven as the build tool. 

Example Project

Step 1: Refer to this article How to Create a Maven Project in IntelliJ IDEA and create a Maven project in IntelliJ IDEA. 

Step 2: Add the following dependencies in your pom.xml file.

<!-- Dependency for okhttp -->
<dependency>
 <groupId>com.squareup.okhttp3</groupId>
 <artifactId>okhttp</artifactId>
 <version>4.2.2</version>
</dependency>

<!-- Dependency for Wiremock-->
<dependency>
 <groupId>com.github.tomakehurst</groupId>
 <artifactId>wiremock</artifactId>
 <version>2.27.2</version>
 <scope>test</scope>
</dependency>

<!-- Dependency for JUnit-->
<dependency>
 <groupId>junit</groupId>
 <artifactId>junit</artifactId>
 <version>4.13-rc-2</version>
 <scope>test</scope>
</dependency>

Below is the complete code for the pom.xml file.

Step 3: Now go to the src > test > java and create a test class named WiremockWithJunit. In this class, we are going to perform the Request Matching with JUnit Test. At first, we have to configure the stub something like this.

private void configStubForPostMethod() {
 configureFor("localhost", 9090);
 stubFor(post(urlPathEqualTo("/testuser"))
 .willReturn(status(200)
 .withBody("Welcome TestUser!")
 .withHeader("content-type", "application/json")));
 }

The code is self-explanatory, so please refer to the code in-depth so you can understand the code easily. Now let's create the Request Body

RequestBody body = new FormBody.Builder()
 .add("username", "testuser")
 .build();

Then call the request in WireMock through OkHttpClient.

OkHttpClient client = new OkHttpClient().newBuilder()
 .build();
Request request = new Request.Builder()
 .url("http://localhost:9090/testuser")
 .method("POST", body)
 .build();
Response response = client.newCall(request).execute();

And finally, assert the response, and you are done 

assertEquals("Welcome TestUser!", response.body().string());

Below is the complete code for the WiremockWithJunit.java class.

Now, let's run our test. And in the below image you can see our test has been passed. 

👁 Image

Example: Regex matching on the path only

Syntax:

urlPathMatching("/your/([a-z1-9]*)")

Now let's demonstrate this with the help of IntelliJ IDEA as the IDE and Maven as the build tool. We are starting from Step 3 as Step 1 and Step 2 will remain similar. 

Step 3: Now go to the src > test > java and create a test class named WiremockWithJunit. At first, we have to configure the stub something like this.

private void configStubForPostMethod() {
 configureFor("localhost", 9090);
 stubFor(post(urlPathMatching("/gfg/([a-z1-9]*)"))
 .willReturn(status(200)
 .withBody("Welcome TestUser!")
 .withHeader("content-type", "application/json")));
 }

The code is self-explanatory, so please refer to the code in-depth so you can understand the code easily. Now let's create the Request Body

RequestBody body = new FormBody.Builder()
 .add("username", "testuser")
 .build();

Then call the request in WireMock through OkHttpClient.

OkHttpClient client = new OkHttpClient().newBuilder()
 .build();
Request request = new Request.Builder()
 .url("http://localhost:9090/gfg/testuser234125")
 .method("POST", body)
 .build();
Response response = client.newCall(request).execute();

Note: Here in the URL you can put anything in the range of [a-z] and [1-9] after /gfg/.

And finally, assert the response, and you are done 

assertEquals("Welcome TestUser!", response.body().string());

Below is the complete code for the WiremockWithJunit.java class.

Similarly, you can also try the demonstration in your IntelliJ IDEA for the following Request Matching.

Equality matching on path and query

Syntax:

urlEqualTo("/your/url?and=query")

Regex matching on path and query

Syntax:

urlMatching("/your/([a-z]*)\\?and=query")

2. Matching Other Attributes

Apart from the URL, all request attributes can be matched using some operators. 

Equality

Syntax:

.withHeader("Content-Type", equalTo("application/xml"))

Case-insensitive equality

Syntax:

.withHeader("Content-Type", equalToIgnoreCase("application/xml"))

3. JSON Equality

It will be a match if the attribute is valid JSON and is a semantic match for the expected value.

Syntax:

.withRequestBody(equalToJson("{ \"name\": "GeeksforGeeks" }"))

4. XML Equality

It will be a match if the attribute value is valid XML and is semantically equal to the expected XML document.

Syntax:

.withRequestBody(equalToXml("<thing>GeeksforGeeks</thing>"))

5. Basic Authentication Matching 

In WireMock, you can also match on HTTP basic authentication. 

Syntax:

stubFor(get(urlEqualTo("/basic-auth")).withBasicAuth("UserName", "Password")