To learn how to set up the Gradle project for Spring Cloud Contract Verifier, read the following sections:
1. Prerequisites
To use Spring Cloud Contract Verifier with WireMock, you must use either a Gradle or a Maven plugin.
If you want to use Spock in your projects, you must separately add the
spock-core and spock-spring modules. See Spock’s
documentation for more information.
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2. Add Gradle Plugin with Dependencies
To add a Gradle plugin with dependencies, you can use code similar to the following:
// build.gradle
plugins {
id "groovy"
// this will work only for GA versions of Spring Cloud Contract
id "org.springframework.cloud.contract" version "${GAVerifierVersion}"
}
dependencyManagement {
imports {
mavenBom "org.springframework.cloud:spring-cloud-contract-dependencies:${GAVerifierVersion}"
}
}
dependencies {
testImplementation "org.codehaus.groovy:groovy-all:${groovyVersion}"
// example with adding Spock core and Spock Spring
testImplementation "org.spockframework:spock-core:${spockVersion}"
testImplementation "org.spockframework:spock-spring:${spockVersion}"
testImplementation 'org.springframework.cloud:spring-cloud-starter-contract-verifier'
}
// settings.gradle
pluginManagement {
plugins {
id "org.springframework.cloud.contract" version "${verifierVersion}"
}
repositories {
// to pick from local .m2
mavenLocal()
// for snapshots
maven { url "https://repo.spring.io/snapshot" }
// for milestones
maven { url "https://repo.spring.io/milestone" }
// for GA versions
gradlePluginPortal()
}
}
// build.gradle
plugins {
id "groovy"
id "org.springframework.cloud.contract"
}
dependencyManagement {
imports {
mavenBom "org.springframework.cloud:spring-cloud-contract-dependencies:${verifierVersion}"
}
}
dependencies {
testImplementation "org.codehaus.groovy:groovy-all:${groovyVersion}"
// example with adding Spock core and Spock Spring
testImplementation "org.spockframework:spock-core:${spockVersion}"
testImplementation "org.spockframework:spock-spring:${spockVersion}"
testImplementation 'org.springframework.cloud:spring-cloud-starter-contract-verifier'
}
// build.gradle
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath "org.springframework.boot:spring-boot-gradle-plugin:${springboot_version}"
classpath "org.springframework.cloud:spring-cloud-contract-gradle-plugin:${verifier_version}"
// here you can also pass additional dependencies such as Pact or Kotlin spec e.g.:
// classpath "org.springframework.cloud:spring-cloud-contract-spec-kotlin:${verifier_version}"
}
}
apply plugin: 'groovy'
apply plugin: 'org.springframework.cloud.contract'
dependencyManagement {
imports {
mavenBom "org.springframework.cloud:spring-cloud-contract-dependencies:${verifier_version}"
}
}
dependencies {
testImplementation "org.codehaus.groovy:groovy-all:${groovyVersion}"
// example with adding Spock core and Spock Spring
testImplementation "org.spockframework:spock-core:${spockVersion}"
testImplementation "org.spockframework:spock-spring:${spockVersion}"
testImplementation 'org.springframework.cloud:spring-cloud-starter-contract-verifier'
}
3. Gradle and Rest Assured 2.0
By default, Rest Assured 3.x is added to the classpath. However, to use Rest Assured 2.x, you can add it to the plugins classpath, as the following listing shows:
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath "org.springframework.boot:spring-boot-gradle-plugin:${springboot_version}"
classpath "org.springframework.cloud:spring-cloud-contract-gradle-plugin:${verifier_version}"
classpath "com.jayway.restassured:rest-assured:2.5.0"
classpath "com.jayway.restassured:spring-mock-mvc:2.5.0"
}
}
depenendencies {
// all dependencies
// you can exclude rest-assured from spring-cloud-contract-verifier
testCompile "com.jayway.restassured:rest-assured:2.5.0"
testCompile "com.jayway.restassured:spring-mock-mvc:2.5.0"
}
That way, the plugin automatically sees that Rest Assured 2.x is present on the classpath and modifies the imports accordingly.
4. Snapshot Versions for Gradle
You can add the additional snapshot repository to your build.gradle
to use snapshot versions,
which are automatically uploaded after every successful build, as the following listing shows:
}
5. Add stubs
By default, Spring Cloud Contract Verifier looks for stubs in the
src/contractTest/resources/contracts
directory. For transitional purposes the plugin
will also look for contracts in src/test/resources/contracts
, however, this directory
is deprecated as of Spring Cloud Contract 3.0.0.
It should also be noted, that with this new Gradle source set, you should also migrate
any base classes used within your contract tests to src/contractTest/{language}
where
{language}
should be replaced with Java or Groovy as needed for your purposes.
The directory that contains stub definitions is treated as a class name, and each stub definition is treated as a single test. Spring Cloud Contract Verifier assumes that it contains at least one level of directories that are to be used as the test class name. If more than one level of nested directories is present, all except the last one is used as the package name. Consider the following structure:
src/contractTest/resources/contracts/myservice/shouldCreateUser.groovy
src/contractTest/resources/contracts/myservice/shouldReturnUser.groovy
Given the preceding structure, Spring Cloud Contract Verifier creates a test class named
defaultBasePackage.MyService
with two methods:
-
shouldCreateUser()
-
shouldReturnUser()
6. Running the Plugin
The plugin registers itself to be invoked before a check
task. If you want it to be
part of your build process, you need do nothing more. If you want only to generate
tests, invoke the generateContractTests
task.
7. Default Setup
The default Gradle Plugin setup creates the following Gradle part of the build (in pseudocode):
contracts {
testFramework ='JUNIT'
testMode = 'MockMvc'
generatedTestJavaSourcesDir = project.file("${project.buildDir}/generated-test-sources/contractTest/java")
generatedTestGroovySourcesDir = project.file("${project.buildDir}/generated-test-sources/contractTest/groovy")
generatedTestResourcesDir = project.file("${project.buildDir}/generated-test-resources/contracts")
contractsDslDir = project.file("${project.projectDir}/src/contractTest/resources/contracts")
basePackageForTests = 'org.springframework.cloud.verifier.tests'
stubsOutputDir = project.file("${project.buildDir}/stubs")
sourceSet = null
}
def verifierStubsJar = tasks.register(type: Jar, name: 'verifierStubsJar', dependsOn: 'generateClientStubs') {
baseName = project.name
classifier = contracts.stubsSuffix
from contractVerifier.stubsOutputDir
}
def copyContracts = tasks.register(type: Copy, name: 'copyContracts') {
from contracts.contractsDslDir
into contracts.stubsOutputDir
}
verifierStubsJar.dependsOn copyContracts
8. Configuring the Plugin
To change the default configuration, you can add a contracts
snippet to your Gradle
configuration, as the following listing shows:
contracts {
testMode = 'MockMvc'
baseClassForTests = 'org.mycompany.tests'
generatedTestJavaSourcesDir = project.file('src/generatedContract')
}
To download contracts from a remote source, you can use the following snippets as needed:
contracts {
// If your contracts exist in a JAR archive published to a Maven repository
contractDependency {
stringNotation = ''
// OR
groupId = ''
artifactId = ''
version = ''
classifier = ''
}
// If your contracts exist in a Git SCM repository
contractRepository {
repositoryUrl = ''
// username = ''
// password = ''
}
// controls the nested location to find the contracts in either the JAR or Git SCM source
contractsPath = ''
}
Since we are using Gradle’s Jar packaging task, there are several options and capabilities that you may wish to utilize to further extend what is created by the verifierStubsJar
. In order to do this, you would use the native mechanisms provided directly by Gradle for customizing an existing task like so:
for the sake of the example, we desire to add a git.properties file to the verifierStubsJar .
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verifierStubsJar {
from("${buildDir}/resources/main/") {
include("git.properties")
}
}
It should also be noted that as of 3.0.0, the default publication has been disabled. As a result this means, that you are able to create any named jar and publish it as you would normally have done via Gradle configuration options. This means that you can build a jar file customized just the way you would like and publish that for absolute full control over the jar’s layout and contents.
9. Configuration Options
-
testMode
: Defines the mode for acceptance tests. By default, the mode is MockMvc, which is based on Spring’s MockMvc. It can also be changed to WebTestClient, JaxRsClient, or Explicit (for real HTTP calls). -
imports
: Creates an array with imports that should be included in the generated tests (for example,['org.myorg.Matchers']
). By default, it creates an empty array. -
staticImports
: Creates an array with static imports that should be included in generated tests(for example,['org.myorg.Matchers.*']
). By default, it creates an empty array. -
basePackageForTests
: Specifies the base package for all generated tests. If not set, the value is picked from the package ofbaseClassForTests
and frompackageWithBaseClasses
. If neither of these values are set, the value is set toorg.springframework.cloud.contract.verifier.tests
. -
baseClassForTests
: Creates a base class for all generated tests. By default, if you use Spock classes, the class isspock.lang.Specification
. -
packageWithBaseClasses
: Defines a package where all the base classes reside. This setting takes precedence overbaseClassForTests
. -
baseClassMappings
: Explicitly maps a contract package to a FQN of a base class. This setting takes precedence overpackageWithBaseClasses
andbaseClassForTests
. -
ignoredFiles
: Uses anAntmatcher
to allow defining stub files for which processing should be skipped. By default, it is an empty array. -
contractsDslDir
: Specifies the directory that contains contracts written by using the GroovyDSL. By default, its value is$projectDir/src/contractTest/resources/contracts
. -
generatedTestSourcesDir
: Specifies the test source directory where tests generated from the Groovy DSL should be placed. (Deprecrated) -
generatedTestJavaSourcesDir
: Specifies the test source directory where Java/JUnit tests generated from the Groovy DSL should be placed. By default, it’s value is$buildDir/generated-tes-sources/contractTest/java
. -
generatedTestGroovySourcesDir
: Specifies the test source directory where Groovy/Spock tests generated from the Groovy DSL should be placed. By default, it’s value is$buildDir/generated-test-sources/contractTest/groovy
. -
generatedTestResourcesDir
: Specifies the test resource directory where resources used by the tests generated from the Groovy DSL should be placed. By default, its value is$buildDir/generated-test-resources/contractTest
. -
stubsOutputDir
: Specifies the directory where the generated WireMock stubs from the Groovy DSL should be placed. -
testFramework
: Specifies the target test framework to be used. Currently, Spock, JUnit 4 (TestFramework.JUNIT
) and JUnit 5 are supported, with JUnit 4 being the default framework. -
contractsProperties
: A map that contains properties to be passed to Spring Cloud Contract components. Those properties might be used by (for example) built-in or custom Stub Downloaders. -
sourceSet
: Source set where the contracts are stored. If not provided will assumecontractTest
(for example,project.sourceSets.contractTest.java
for JUnit orproject.sourceSets.contractTest.groovy
for Spock).
You can use the following properties when you want to specify the location of the JAR that contains the contracts:
-
contractDependency
: Specifies the Dependency that providesgroupid:artifactid:version:classifier
coordinates. You can use thecontractDependency
closure to set it up. -
contractsPath
: Specifies the path to the jar. If contract dependencies are downloaded, the path defaults togroupid/artifactid
, wheregroupid
is slash separated. Otherwise, it scans contracts under the provided directory. -
contractsMode
: Specifies the mode for downloading contracts (whether the JAR is available offline, remotely, and so on). -
deleteStubsAfterTest
: If set tofalse
, does not remove any downloaded contracts from temporary directories. -
failOnNoContracts
: When enabled, will throw an exception when no contracts were found. Defaults totrue
. -
failOnInProgress
: If set totrue
, then, if any contracts that are in progress are found, they break the build. On the producer side, you need to be explicit about the fact that you have contracts in progress and take into consideration that you might be causing false positive test results on the consumer side. Defaults totrue
.
There is also the contractRepository { … }
closure that contains the following properties
-
repositoryUrl
: The URL to the repository with contract definitions -
username
: The repository username -
password
: The repository password -
proxyPort
: The port of the proxy -
proxyHost
: The host of the proxy -
cacheDownloadedContracts
: If set totrue
, caches the folder where non-snapshot contract artifacts got downloaded. Defaults totrue
.
You can also turn on the following experimental features in the plugin:
-
convertToYaml
: Converts all DSLs to the declarative YAML format. This can be extremely useful when you use external libraries in your Groovy DSLs. By turning this feature on (by setting it totrue
), you need not add the library dependency on the consumer side. -
assertJsonSize
: You can check the size of JSON arrays in the generated tests. This feature is disabled by default.
10. Single Base Class for All Tests
When using Spring Cloud Contract Verifier in MockMvc (the default), you need to create a base specification for all generated acceptance tests. In this class, you need to point to an endpoint, which should be verified. The following example shows how to do so:
abstract class BaseMockMvcSpec extends Specification {
def setup() {
RestAssuredMockMvc.standaloneSetup(new PairIdController())
}
void isProperCorrelationId(Integer correlationId) {
assert correlationId == 123456
}
void isEmpty(String value) {
assert value == null
}
}
If you use Explicit
mode, you can use a base class to initialize the whole tested application,
as you might see in regular integration tests. If you use the JAXRSCLIENT
mode, this
base class should also contain a protected WebTarget webTarget
field. Right now, the
only option to test the JAX-RS API is to start a web server.
11. Different Base Classes for Contracts
If your base classes differ between contracts, you can tell the Spring Cloud Contract plugin which class should get extended by the autogenerated tests. You have two options:
-
Follow a convention by providing the
packageWithBaseClasses
-
Provide explicit mapping by using
baseClassMappings
11.1. By Convention
The convention is such that, if you have a contract in (for example)
src/contractTest/resources/contract/foo/bar/baz/
and set the value of the
packageWithBaseClasses
property to com.example.base
, then Spring Cloud Contract
Verifier assumes that there is a BarBazBase
class under the com.example.base
package.
In other words, the system takes the last two parts of the package, if they exist, and
forms a class with a Base
suffix. This rule takes precedence over baseClassForTests
.
The following example shows how it works in the contracts
closure:
packageWithBaseClasses = 'com.example.base'
11.2. By Mapping
You can manually map a regular expression of the contract’s package to the fully qualified
name of the base class for the matched contract. You have to provide a list called
baseClassMappings
that consists of baseClassMapping
objects that take a
contractPackageRegex
to baseClassFQN
mapping. Consider the following example:
baseClassForTests = "com.example.FooBase"
baseClassMappings {
baseClassMapping('.*/com/.*', 'com.example.ComBase')
baseClassMapping('.*/bar/.*': 'com.example.BarBase')
}
Assume that you have contracts in the following directories:
-
src/contractTest/resources/contract/com/
-
src/contractTest/resources/contract/foo/
By providing baseClassForTests
, we have a fallback in case mapping did not succeed.
(You could also provide the packageWithBaseClasses
as a fallback.) That way, the tests
generated from src/contractTest/resources/contract/com/
contracts extend the
com.example.ComBase
, whereas the rest of the tests extend com.example.FooBase
.
12. Invoking Generated Tests
To ensure that the provider side is compliant with your defined contracts, you need to run the following command:
./gradlew contractTest
13. Publishing Stubs to Artifact Repository
If you use an binary artifact repository to keep the stubs,
you will need to configure the publishing section for Gradle to
include the verifierStubsJar
. To do that, you can use the
example configuration below:
apply plugin: 'maven-publish'
publishing {
publications {
maven(MavenPublication) {
// other configuration
artifact verifierStubsJar
}
}
}
Since 3.0.0, the internal stubs publication has been deprecated
and disabled by default. It is recommended to include the
verifierStubsJar
with one of your own publications.
14. Pushing Stubs to SCM
If you use the SCM repository to keep the contracts and
stubs, you might want to automate the step of pushing stubs to
the repository. To do that, you can call the pushStubsToScm
task by running the following command:
$ ./gradlew pushStubsToScm
Under [scm-stub-downloader], you can find all possible
configuration options that you can pass either through
the contractsProperties
field (for example, contracts { contractsProperties = [foo:"bar"] }
),
through the contractsProperties
method (for example, contracts { contractsProperties([foo:"bar"]) }
),
or through a system property or an environment variable.
15. Spring Cloud Contract Verifier on the Consumer Side
In a consuming service, you need to configure the Spring Cloud Contract Verifier plugin
in exactly the same way as in the case of a provider. If you do not want to use Stub Runner,
you need to copy the contracts stored in src/contractTest/resources/contracts
and generate
WireMock JSON stubs by using the following command:
./gradlew generateClientStubs
The stubsOutputDir option has to be set for stub generation to work.
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When present, you can use JSON stubs in automated tests to consume a service. The following example shows how to do so:
@ContextConfiguration(loader == SpringApplicationContextLoader, classes == Application)
class LoanApplicationServiceSpec extends Specification {
@ClassRule
@Shared
WireMockClassRule wireMockRule == new WireMockClassRule()
@Autowired
LoanApplicationService sut
def 'should successfully apply for loan'() {
given:
LoanApplication application =
new LoanApplication(client: new Client(clientPesel: '12345678901'), amount: 123.123)
when:
LoanApplicationResult loanApplication == sut.loanApplication(application)
then:
loanApplication.loanApplicationStatus == LoanApplicationStatus.LOAN_APPLIED
loanApplication.rejectionReason == null
}
}
In the preceding example, LoanApplication
makes a call to the FraudDetection
service.
This request is handled by a WireMock server configured with stubs that were generated by
Spring Cloud Contract Verifier.