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Pact Junit 5 Extension

Dependency#

The library is available on maven central using:

  • group-id = au.com.dius.pact.provider
  • artifact-id = junit5
  • version-id = 4.1.x

Overview#

For writing Pact verification tests with JUnit 5, there is an JUnit 5 Invocation Context Provider that you can use with the @TestTemplate annotation. This will generate a test for each interaction found for the pact files for the provider.

To use it, add the @Provider and one of the pact source annotations to your test class (as per a JUnit 4 test), then add a method annotated with @TestTemplate and @ExtendWith(PactVerificationInvocationContextProvider.class) that takes a PactVerificationContext parameter. You will need to call verifyInteraction() on the context parameter in your test template method.

For example:

@Provider("myAwesomeService")
@PactFolder("pacts")
public class ContractVerificationTest {
@TestTemplate
@ExtendWith(PactVerificationInvocationContextProvider.class)
void pactVerificationTestTemplate(PactVerificationContext context) {
context.verifyInteraction();
}
}

For details on the provider and pact source annotations, refer to the Pact junit runner docs.

Test target#

You can set the test target (the object that defines the target of the test, which should point to your provider) on the PactVerificationContext, but you need to do this in a before test method (annotated with @BeforeEach). There are three different test targets you can use: HttpTestTarget, HttpsTestTarget and MessageTestTarget.

For example:

@BeforeEach
void before(PactVerificationContext context) {
context.setTarget(HttpTestTarget.fromUrl(new URL(myProviderUrl)));
// or something like
// context.setTarget(new HttpTestTarget("localhost", myProviderPort, "/"));
}

HttpTestTarget#

HttpTestTarget accepts the following options:

OptionTypeDefaultDescription
hostStringlocalhostThe hostname to use to access the provider
portInt8080The port the provider is running on
pathString"/"The base path the provider is mounted on
httpClientFactory() -> IHttpClientFactoryDefault FactoryCallback used to override the HTTP client factory

HttpsTestTarget#

HttpsTestTarget accepts the following options:

OptionTypeDefaultDescription
hostStringlocalhostThe hostname to use to access the provider
portInt8443The port the provider is running on
pathString"/"The base path the provider is mounted on
insecureBooleanfalseDisables the standard TLS verification used with HTTPS connections
httpClientFactory() -> IHttpClientFactoryDefault FactoryCallback used to override the HTTP client factory

MessageTestTarget#

MessageTestTarget accepts the following options:

OptionTypeDefaultDescription
packagesToScanList<String>empty ListThe Java packages to scan to find classes with annotated methods. If your methods are on your test class, you don't need to supply a value for this.
classLoaderClassLoader?nullClass loader to use to load the classes with annotated methods

!! Important note for Maven users !!#

If you use Maven to run your tests, you will have to make sure that the Maven Surefire plugin is at least version 2.22.1 and configured to use an isolated classpath.

For example, configure it by adding the following to your POM:

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
<configuration>
<useSystemClassLoader>false</useSystemClassLoader>
</configuration>
</plugin>

For Message Tests and Spring and Maven#

If you are using Spring (or Springboot), and want to have values injected into your test, you need to ensure that the same class loader is used to execute your annotated test method as Spring is using to inject the values. In particular, options like the Maven Surefire plugin's forkCount == 0 can impact this. Either don't supply any packages to scan (this will use the default class loader and the annotated methods have to be on your test class), or you can provide the classloader to use as the second parameter to MessageTestTarget.

Provider State Methods#

Provider State Methods work in the same way as with JUnit 4 tests, refer to the Pact junit runner docs.

Using multiple classes for the state change methods#

If you have a large number of state change methods, you can split things up by moving them to other classes. You will need to specify the additional classes on the test context in a Before method. Do this with the withStateHandler or setStateHandlers methods. See StateAnnotationsOnAdditionalClassTest for an example.

Modifying the requests before they are sent#

Important Note: You should only use this feature for things that can not be persisted in the pact file. By modifying the request, you are potentially modifying the contract from the consumer tests!

NOTE: JUnit 5 tests do not use @TargetRequestFilter

Sometimes you may need to add things to the requests that can't be persisted in a pact file. Examples of these would be authentication tokens, which have a small life span. The Http and Https test targets support injecting the request that will executed into the test template method. You can then add things to the request before calling the verifyInteraction() method.

For example to add a header:

@TestTemplate
@ExtendWith(PactVerificationInvocationContextProvider.class)
void testTemplate(PactVerificationContext context, HttpRequest request) {
// This will add a header to the request
request.addHeader("X-Auth-Token", "1234");
context.verifyInteraction();
}

Objects that can be injected into the test methods#

You can inject the following objects into your test methods (just like the PactVerificationContext). They will be null if injected before the supported phase.

ObjectCan be injected from phaseDescription
PactVerificationContext@BeforeEachThe context to use to execute the interaction test
PactanyThe Pact model for the test
InteractionanyThe Interaction model for the test
HttpRequest@TestTemplateThe request that is going to be executed (only for HTTP and HTTPS targets)
ProviderVerifier@TestTemplateThe verifier instance that is used to verify the interaction

Allowing the test to pass when no pacts are found to verify (version 4.0.7+)#

By default, the test will fail with an exception if no pacts were found to verify. This can be overridden by adding the @IgnoreNoPactsToVerify annotation to the test class. For this to work, you test class will need to be able to receive null values for any of the injected parameters.

Overriding the handling of a body data type#

NOTE: version 4.1.3+

By default, bodies will be handled based on their content types. For binary contents, the bodies will be base64 encoded when written to the Pact file and then decoded again when the file is loaded. You can change this with an override property: pact.content_type.override.<TYPE>.<SUBTYPE>=text|json|binary. For instance, setting pact.content_type.override.application.pdf=text will treat PDF bodies as a text type and not encode/decode them.

Controlling the generation of diffs#

NOTE: version 4.2.7+

When there are mismatches with large bodies the calculation of the diff can take a long time . You can turn off the generation of the diffs with the JVM system property: pact.verifier.generateDiff=true|false|<dataSize>, where dataSize, if specified, must be a valid data size (for instance 100kb or 1mb). This will turn off the diff calculation for payloads that exceed this size.

For instance, setting pact.verifier.generateDiff=false will turn off the generation of diffs for all bodies, while pact.verifier.generateDiff=512kb will only turn off the diffs if the actual or expected body is larger than 512kb.

Pending Pact Support (version 4.1.0 and later)#

If your Pact broker supports pending pacts, you can enable support for that by enabling that on your Pact broker annotation or with JVM system properties. You also need to provide the tags that will be published with your provider's verification results. The broker will then label any pacts found that don't have a successful verification result as pending. That way, if they fail verification, the verifier will ignore those failures and not fail the build.

For example, with annotation:

@Provider("Activity Service")
@PactBroker(host = "test.pactflow.io", tags = {"test"}, scheme = "https",
enablePendingPacts = "true",
providerTags = "master"
)
public class PactJUnitTest {

You can also use the pactbroker.enablePending and pactbroker.providerTags JVM system properties.

Then any pending pacts will not cause a build failure.

Work In Progress (WIP) Pact Support (version 4.1.5 and later)#

WIP pacts work in the same way as with JUnit 4 tests, refer to the Pact junit runner docs.

Last updated on by Github Action