JUnit 5 support for Pact consumer tests

Dependency

The library is available on maven central using:

• group-id = au.com.dius.pact.consumer
• artifact-id = junit5
• version-id = 4.1.0

Usage

1. Add the Pact consumer test extension to the test class.

To write Pact consumer tests with JUnit 5, you need to add @ExtendWith(PactConsumerTestExt) to your test class. This replaces the PactRunner used for JUnit 4 tests. The rest of the test follows a similar pattern as for JUnit 4 tests.

@ExtendWith(PactConsumerTestExt.class)

class ExampleJavaConsumerPactTest {

2. create a method annotated with @Pact that returns the interactions for the test

For each test (as with JUnit 4), you need to define a method annotated with the @Pact annotation that returns the interactions for the test.

@Pact(provider="ArticlesProvider", consumer="test_consumer")

public RequestResponsePact createPact(PactDslWithProvider builder) {

return builder

.given("test state")

.uponReceiving("ExampleJavaConsumerPactTest test interaction")

.path("/articles.json")

.method("GET")

.willRespondWith()

.status(200)

.body("{\"responsetest\": true}")

.toPact();

}

3. Link the mock server with the interactions for the test with @PactTestFor

Then the final step is to use the @PactTestFor annotation to tell the Pact extension how to setup the Pact test. You can either put this annotation on the test class, or on the test method. For examples see ArticlesTest and MultiTest.

The @PactTestFor annotation allows you to control the mock server in the same way as the JUnit 4 PactProviderRule. It allows you to set the hostname to bind to (default is localhost) and the port (default is to use a random port). You can also set the Pact specification version to use (default is V3).

@ExtendWith(PactConsumerTestExt.class)

@PactTestFor(providerName = "ArticlesProvider")

public class ExampleJavaConsumerPactTest {

NOTE on the hostname: The mock server runs in the same JVM as the test, so the only valid values for hostname are:

hostname	result
localhost	binds to the address that localhost points to (normally the loopback adapter)
127.0.0.1 or ::1	binds to the loopback adapter
host name	binds to the default interface that the host machines DNS name resolves to
0.0.0.0 or ::	binds to the all interfaces on the host machine

Matching the interactions by provider name

If you set the providerName on the @PactTestFor annotation, then the first method with a @Pact annotation with the same provider name will be used. See ArticlesTest for an example.

Matching the interactions by method name

If you set the pactMethod on the @PactTestFor annotation, then the method with the provided name will be used (it still needs a @Pact annotation). See MultiTest for an example.

Injecting the mock server into the test

You can get the mock server injected into the test method by adding a MockServer parameter to the test method.

@Test

void test(MockServer mockServer) throws IOException {

HttpResponse httpResponse = Request.Get(mockServer.getUrl() + "/articles.json").execute().returnResponse();

assertThat(httpResponse.getStatusLine().getStatusCode(), is(equalTo(200)));

}

This helps with getting the base URL of the mock server, especially when a random port is used.

Changing the directory pact files are written to

By default, pact files are written to target/pacts (or build/pacts if you use Gradle), but this can be overwritten with the pact.rootDir system property. This property needs to be set on the test JVM as most build tools will fork a new JVM to run the tests.

For Gradle, add this to your build.gradle:

test {

systemProperties['pact.rootDir'] = "$buildDir/custom-pacts-directory"

}

For maven, use the systemPropertyVariables configuration:

<project>

[...]

<build>

<plugins>

<plugin>

<groupId>org.apache.maven.plugins</groupId>

<artifactId>maven-surefire-plugin</artifactId>

<version>2.18</version>

<configuration>

<systemPropertyVariables>

<pact.rootDir>some/other/directory</pact.rootDir>

<buildDirectory>${project.build.directory}</buildDirectory>

[...]

</systemPropertyVariables>

</configuration>

</plugin>

</plugins>

</build>

[...]

</project>

For SBT:

fork in Test := true,

javaOptions in Test := Seq("-Dpact.rootDir=some/other/directory")

Using @PactFolder annotation

You can override the directory the pacts are written in a test by adding the @PactFolder annotation to the test class.

Forcing pact files to be overwritten

By default, when the pact file is written, it will be merged with any existing pact file. To force the file to be overwritten, set the Java system property pact.writer.overwrite to true.

Unsupported

The current implementation does not support tests with multiple providers. This will be added in a later release.

Having values injected from provider state callbacks

You can have values from the provider state callbacks be injected into most places (paths, query parameters, headers, bodies, etc.). This works by using the V3 spec generators with provider state callbacks that return values. One example of where this would be useful is API calls that require an ID which would be auto-generated by the database on the provider side, so there is no way to know what the ID would be beforehand.

The following DSL methods all you to set an expression that will be parsed with the values returned from the provider states:

For JSON bodies, use valueFromProviderState.
For headers, use headerFromProviderState.
For query parameters, use queryParameterFromProviderState.
For paths, use pathFromProviderState.

For example, assume that an API call is made to get the details of a user by ID. A provider state can be defined that specifies that the user must be exist, but the ID will be created when the user is created. So we can then define an expression for the path where the ID will be replaced with the value returned from the provider state callback.

.pathFromProviderState("/api/users/${id}", "/api/users/100")

You can also just use the key instead of an expression:

.valueFromProviderState('userId', 'userId', 100) // will look value using userId as the key

Using HTTPS

You can enable a HTTPS mock server by setting https=true on the @PactTestFor annotation. Note that this mock server will use a self-signed certificate, so any client code will need to accept self-signed certificates.