How to generate both spring restdocs and Pact.io pact from junit test? - junit4

Question

Using spring boot and mockmvc , I have test class with following #beforeEach method:
#BeforeEach
void setUp(WebApplicationContext context,
RestDocumentationContextProvider restDocumentation) {
MockMvcRestDocumentationConfigurer configurer = documentationConfiguration(restDocumentation);
configurer.operationPreprocessors()
.withRequestDefaults(prettyPrint())
.withResponseDefaults(prettyPrint());
configurer.snippets()
.withDefaults(
httpRequest(),
httpResponse()
);
this.mockMvc = MockMvcBuilders.webAppContextSetup(context)
.apply(configurer)
.build();
and the following test method:
#Test
void createAdminHttpRequest() throws Exception {
var adminDTO = HandlerTestObjectGenerator.createFixedAdminDTO();
mockMvc.perform(
RestDocumentationRequestBuilders
.post("/api/admins")
.content(objectMapper.writeValueAsString(adminDTO))
.contentType(MediaType.APPLICATION_JSON_UTF8)
).andExpect(status().isCreated())
.andDo(document("create-admin",
preprocessRequest(),
preprocessResponse(),
requestFields(
usernameFieldDescriptor,
passwordFieldDescriptor,
rolesFieldDescriptor
),
responseFields(
admin_adminIdFieldDescriptor,
admin_usernameFieldDescriptor,
admin_rolesFieldDescriptor
),
SpringCloudContractRestDocs.dslContract(),
));
}
This test works well and generates both spring rest docs documentation and groovy contract.
But for front-end (react) testing, I need to generate Pact.io contract, which is framework independent.
Question
So, my question is if it is possible to generate both spring rest docs and pact.io pact using single #Test method?
My research
What I have found so far is that pacts are generated from #Pact annotated methods using its own rest builder.
Additonally, I have found this conversation:
https://gitter.im/spring-cloud/spring-cloud-contract/archives/2018/08/06 and I am trying to implement own maven plugin to convert groovy contracts to pacts, but there seems to be error in the BodyConverter class and I am getting the following exception:
java.lang.UnsupportedOperationException: use the array(String name) form
at au.com.dius.pact.consumer.dsl.PactDslJsonBody.array(PactDslJsonBody.java:673)
My maven plugin code samples:
Inicialization:
private PactContractConverter pactContractConverter = new PactContractConverter();
private ContractVerifierDslConverter contractDslConverter = new ContractVerifierDslConverter();
Conversion:
private void processFiles(List<File> contractFiles) throws Exception {
for(File file : contractFiles) {
logger.info("Processing " + file.getAbsolutePath());
Collection<Contract> contracts = contractDslConverter.convertFrom(file);
Collection<Pact> pacts = pactContractConverter.convertTo(contracts);
String jsonPacts = mapper.writeValueAsString(pactContractConverter.store(pacts));
File pactsFile = new File(outputDir, file.getName() + "_pact.json");
FileUtils.writeByteArrayToFile(pactsFile, jsonPacts.getBytes());
logger.info("Generated pact file: " + pactsFile.getAbsolutePath());
}
}
But I am getting the exception mentioned above. There is a direct call to the method, which throws UnsupportedOperationException. I found other method array(String name), but that seems not to be called from the converter code.

Answer 1

Let's begin with this statement:
But for front-end (react) testing, I need to generate Pact.io contract, which is framework independent.
You can use Spring Cloud Contract in the polyglot world. Just use Docker (https://spring.io/blog/2018/02/13/spring-cloud-contract-in-a-polyglot-world) and https://cloud.spring.io/spring-cloud-static/spring-cloud-contract/2.2.0.RELEASE/reference/html/docker-project.html
Coming back to your question
So, my question is if it is possible to generate both spring rest docs and pact.io pact using single #Test method?
Let's do it in a different way... Since you already have the DSLs, I guess you would like to also get the Pact files. If you check the documentation under this section (https://cloud.spring.io/spring-cloud-static/spring-cloud-contract/2.2.0.RELEASE/reference/html/howto.html#how-to-generate-pact-from-scc) you'll see exactly the answer to your question. It's enough to add a plugin that after your tests have generated the DSLs will convert those DSLs to something else, e.g. Pact files.
Example of using Maven plugin
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.6.0</version>
<executions>
<execution>
<id>convert-dsl-to-pact</id>
<phase>process-test-classes</phase>
<configuration>
<classpathScope>test</classpathScope>
<mainClass>
org.springframework.cloud.contract.verifier.util.ToFileContractsTransformer
</mainClass>
<arguments>
<argument>
org.springframework.cloud.contract.verifier.spec.pact.PactContractConverter
</argument>
<argument>${project.basedir}/target/pacts</argument>
<argument>
${project.basedir}/src/test/resources/contracts
</argument>
</arguments>
</configuration>
<goals>
<goal>java</goal>
</goals>
</execution>
</executions>
</plugin>
If you modify the ${project.basedir}/src/test/resources/contracts to point to the location where the DSLs got dumped from your REST Docs tests, you'll get the PACT files dumped to ${project.basedir}/target/pacts. Below you have a similar example for Gradle
task convertContracts(type: JavaExec) {
main = "org.springframework.cloud.contract.verifier.util.ToFileContractsTransformer"
classpath = sourceSets.test.compileClasspath
args("org.springframework.cloud.contract.verifier.spec.pact.PactContractConverter",
"${project.rootDir}/build/pacts", "${project.rootDir}/src/test/resources/contracts")
}