This repository contains library for generating pact files out of Feign clients.
To generate Pact files, tests for each interaction between service consumer and provider must be written. As number of microservices and hence number of interaction grows, writing such tests becomes bigger burden. As pact files are currently the only format of expectations supported by Judge Dredd, automatic generation of Pact files makes it much faster to perform contract tests. What is more developers don't need to update Pact tests each time interactions between services is changed.
First, the most important thing is that pact-gen is only able to generate pact files out of Feign clients (at the moment - we have support for other http clients in our roadmap).
Our main goal was to create library that doesn't make you write additional boilerplate. However it was not possible to generate fully useful pact files by using only Feign clients features.
Here are conventions that we made:
@FeignClient
annotation has a property name
- value of that property will be used
as a provider name@InteractionInfo
- more about this annotation can be found hereAdd pact-gen as a dependency to your project:
if you are using gradle add it to build.gradle:
dependencies {
...
compile "com.hltech:pact-gen:version"
}
if you are using maven add it to pom.xml:
<dependencies>
<dependency>
<groupId>com.hltech</groupId>
<artifactId>pact-gen</artifactId>
<version>version</version>
</dependency>
</dependencies>
After your build tool will be able to resolve that dependency you just have to write simple integration test (you need your application context so your object mapper is properly configured). Such test may look like this:
package com.hltech.pact.gen.example
import com.fasterxml.jackson.databind.ObjectMapper
import com.hltech.pact.gen.PactGenerator
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.boot.test.context.SpringBootTest
import spock.lang.Specification
@SpringBootTest
class ContractTestsGenerator extends Specification {
@Autowired
private ObjectMapper objectMapper
private PactGenerator pactGenerator = new PactGenerator()
def "should generate pact file"() {
expect:
pactGenerator.writePactFiles("com.hltech.rest", "consumer-name", objectMapper, new File("build/pacts/"))
}
}
This test will:
com.hltech.rest
and its children looking for Feign clientsYou can take profit of your generated pact files by testing via Judge-D - an open-source engine for contract testing.
We have added custom annotation @InteractionInfo
that contains information about:
@InteractionInfo(responseStatus = HttpStatus.OK)
- will add information to pact file that expected
status is 200 OK
@InteractionInfo(responseStatus = HttpStatus.OK, responseHeaders = {"key1=val1", "key2=val2"})
- will
add information to pact file, that expected status is 200 OK
and that we expect two headers in response:
first with name key1
and value val1
and second with name key2
and value val2
@InteractionInfo(responseStatus = HttpStatus.OK, description = "Update test object in the test service")
- will
add information to pact file, that expected status is 200 OK
and that interaction is called
Update test object in the test service
@InteractionInfo(responseStatus = HttpStatus.OK, emptyBodyExpected = true)
- will add information to pact file
that expected status is 200 OK
and that (despite declared return type) we expect response to be empty.
@InteractionInfo
can be aggregated thanks to @InteractionsInfo
annotation - example usage:
@InteractionsInfo({
@InteractionInfo(responseStatus = HttpStatus.NOT_FOUND),
@InteractionInfo(responseStatus = HttpStatus.ACCEPTED)
})
such annotations on method will add information to pact file that we expect rest service to be able
to return any of 404 NOT FOUND
and 202 ACCEPTED
HTTP statuses.
pact-gen is MIT licensed.