[[getting-started]]
= Getting Started
include::_attributes.adoc[]

If you are getting started with {project-full-name} or Spring in general, start by reading
this section. It answers the basic "`what?`", "`how?`" and "`why?`" questions. It
includes an introduction to {project-full-name}, along with installation instructions. We then
walk you through building your first {project-full-name} application, discussing some core
principles as we go.

[[getting-started-introducing-spring-cloud-contract]]
== Introducing Spring Cloud Contract

Spring Cloud Contract moves TDD to the level of software architecture.
It lets you perform consumer-driven and producer-driven contract testing.

[[getting-started-introducing-spring-cloud-contract-history]]
=== History

Before becoming Spring Cloud Contract, this project was called https://github.com/Codearte/accurest[Accurest].
It was created by https://twitter.com/mgrzejszczak[Marcin Grzejszczak] and https://twitter.com/jkubrynski[Jakub Kubrynski]
from (https://github.com/Codearte[Codearte]).

The `0.1.0` release took place on 26 Jan 2015, and it became stable with `1.0.0` release on 29 Feb 2016.

[[getting-started-introducing-spring-cloud-contract-why]]
==== Why Do You Need It?

Assume that we have a system that consists of multiple microservices, as the following
image shows:

image::Deps.png[Microservices Architecture]

[[getting-started-introducing-spring-cloud-contract-testing-issues]]
==== Testing Issues

If we want to test the application in the top left corner of the image in the preceding
section to determine whether it can communicate with other services, we could do one of
two things:

- Deploy all microservices and perform end-to-end tests.
- Mock other microservices in unit and integration tests.

Both have their advantages but also a lot of disadvantages.

*Deploy all microservices and perform end-to-end tests*

Advantages:

- Simulates production.
- Tests real communication between services.

Disadvantages:

- To test one microservice, we have to deploy six microservices, a couple of databases,
and other items.
- The environment where the tests run is locked for a single suite of tests (nobody else
would be able to run the tests in the meantime).
- They take a long time to run.
- The feedback comes very late in the process.
- They are extremely hard to debug.

*Mock other microservices in unit and integration tests*

Advantages:

- They provide very fast feedback.
- They have no infrastructure requirements.

Disadvantages:

- The implementor of the service creates stubs that might have nothing to do with
reality.
- You can go to production with passing tests and failing production.

To solve the aforementioned issues, Spring Cloud Contract was created. The main idea is to
give you very fast feedback, without the need to set up the
whole world of microservices. If you work on stubs, then the only applications you need
are those that your application directly uses. The following image shows the relationship
of stubs to an application:

image::Stubs2.png[Stubbed Services]

Spring Cloud Contract gives you the certainty that the stubs that you use were
created by the service that you call. Also, if you can use them, it means that they
were tested against the producer's side. In short, you can trust those stubs.

[[getting-started-introducing-spring-cloud-contract-purposes]]
=== Purposes

The main purposes of Spring Cloud Contract are:

- To ensure that HTTP and messaging stubs (used when developing the client) do exactly
what the actual server-side implementation does.
- To promote the ATDD (acceptance test-driven development) method, and the microservices architectural style.
- To provide a way to publish changes in contracts that are immediately visible on both sides.
- To generate boilerplate test code to be used on the server side.

By default, Spring Cloud Contract integrates with http://wiremock.org[Wiremock] as the HTTP server stub.

IMPORTANT: Spring Cloud Contract's purpose is NOT to start writing business
features in the contracts. Assume that we have a business use case of fraud check. If a
user can be a fraud for 100 different reasons, we would assume that you would create two
contracts, one for the positive case and one for the negative case. Contract tests are
used to test contracts between applications, not to simulate full behavior.

[[getting-started-what-is-a-contract]]
=== What Is a Contract?

As consumers of services, we need to define what exactly we want to achieve. We need to
formulate our expectations. That is why we write contracts. In other words, a contract is
an agreement on how the API or message communication should look. Consider the following example:

Assume that you want to send a request that contains the ID of a client company and the
amount it wants to borrow from us. You also want to send it to the `/fraudcheck` URL by using
the `PUT` method. The following listing shows a contract to check whether a client should
be marked as a fraud in both Groovy and YAML:

====
[source,groovy,indent=0,role="primary"]
.groovy
----
include::{introduction_url}/samples/standalone/dsl/http-server/src/test/resources/contracts/fraud/shouldMarkClientAsFraud.groovy[]
----
////

////
[source,yaml,indent=0,role="secondary"]
.yaml
----
include::{introduction_url}/samples/standalone/dsl/http-server/src/test/resources/contracts/yml/fraud/shouldMarkClientAsFraud.yml[]
----
====

IMPORTANT: It is expected that contracts are coming from a **trusted source**. You should never download nor interact with contracts coming from untrusted locations.

[[getting-started-three-second-tour]]
== A Three-second Tour

This very brief tour walks through using Spring Cloud Contract. It consists of the
following topics:

* <<getting-started-three-second-tour-producer>>
* <<getting-started-three-second-tour-consumer>>

You can find a somewhat longer tour
<<getting-started-first-application,here>>.

The following UML diagram shows the relationship of the parts within Spring Cloud Contract:

[plantuml, getting-started-three-second, png]
----
"API Producer"->"API Producer": add Spring Cloud \nContract (SCC) plugin
"API Producer"->"API Producer": add SCC Verifier dependency
"API Producer"->"API Producer": define contracts
"API Producer"->"Build": run build
"Build"->"SCC Plugin": generate \ntests, stubs and stubs \nartifact (e.g. stubs-jar)
"Build"->"Stub Storage": upload contracts \nand stubs and the project arifact
"Build"->"API Producer": Build successful
"API Consumer"->"API Consumer": add SCC Stub Runner \ndependency
"API Consumer"->"API Consumer": write a SCC Stub Runner \nbased contract test
"SCC Stub Runner"->"Stub Storage": test asks for [API Producer] stubs
"Stub Storage"->"SCC Stub Runner": fetch the [API Producer] stubs
"SCC Stub Runner"->"SCC Stub Runner": run in memory\n HTTP server stubs
"API Consumer"->"SCC Stub Runner": send a request \nto the HTTP server stub
"SCC Stub Runner"->"API Consumer": communication is correct
----

[[getting-started-three-second-tour-producer]]
=== On the Producer Side

To start working with Spring Cloud Contract, you can add files with REST or messaging contracts
expressed in either Groovy DSL or YAML to the contracts directory, which is set by the
`contractsDslDir` property. By default, it is `$rootDir/src/test/resources/contracts`.

Then you can add the Spring Cloud Contract Verifier dependency and plugin to your build file, as
the following example shows:

====
[source,xml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-server/pom.xml[tags=verifier_test_dependencies,indent=0]
----
====

The following listing shows how to add the plugin, which should go in the build/plugins
portion of the file:

====
[source,xml,indent=0]
----
<plugin>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-contract-maven-plugin</artifactId>
	<version>${spring-cloud-contract.version}</version>
	<extensions>true</extensions>
</plugin>
----
====

Running `./mvnw clean install` automatically generates tests that verify the application
compliance with the added contracts. By default, the tests get generated under
`org.springframework.cloud.contract.verifier.tests.`.

As the implementation of the functionalities described by the contracts is not yet
present, the tests fail.

To make them pass, you must add the correct implementation of either handling HTTP
requests or messages. Also, you must add a base test class for auto-generated
tests to the project. This class is extended by all the auto-generated tests, and it
should contain all the setup information necessary to run them (for example `RestAssuredMockMvc`
controller setup or messaging test setup).

The following example, from `pom.xml`, shows how to specify the base test class:

====
[source,xml,indent=0]
----
<build>
        <plugins>
            <plugin>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-contract-maven-plugin</artifactId>
                <version>2.1.2.RELEASE</version>
                <extensions>true</extensions>
                <configuration>
                    <baseClassForTests>com.example.contractTest.BaseTestClass</baseClassForTests> <1>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
----
<1> The `baseClassForTests` element lets you specify your base test class. It must be a child
of a `configuration` element within `spring-cloud-contract-maven-plugin`.
====

Once the implementation and the test base class are in place, the tests pass, and both the
application and the stub artifacts are built and installed in the local Maven repository.
You can now merge the changes, and you can publish both the application and the stub artifacts
in an online repository.

[[getting-started-three-second-tour-consumer]]
=== On the Consumer Side

You can use `Spring Cloud Contract Stub Runner` in the integration tests to get a running
WireMock instance or messaging route that simulates the actual service.

To do so, add the dependency to `Spring Cloud Contract Stub Runner`, as the
following example shows:

====
[source,xml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-client/pom.xml[tags=stub_runner,indent=0]
----
====

You can get the Producer-side stubs installed in your Maven repository in either of two
ways:

* By checking out the Producer side repository and adding contracts and generating the stubs
by running the following commands:
+
====
[source,bash,indent=0]
----
$ cd local-http-server-repo
$ ./mvnw clean install -DskipTests
----
====

TIP: The tests are being skipped because the producer-side contract implementation is not
in place yet, so the automatically-generated contract tests fail.

* By getting already-existing producer service stubs from a remote repository. To do so,
pass the stub artifact IDs and artifact repository URL as `Spring Cloud Contract
Stub Runner` properties, as the following example shows:
+
====
[source,yaml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-client/src/test/resources/application-test-repo.yaml[]
----
====

Now you can annotate your test class with `@AutoConfigureStubRunner`. In the annotation,
provide the `group-id` and `artifact-id` values for `Spring Cloud Contract Stub Runner` to
run the collaborators' stubs for you, as the following example shows:

====
[source,java, indent=0]
----
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.NONE)
@AutoConfigureStubRunner(ids = {"com.example:http-server-dsl:+:stubs:6565"},
		stubsMode = StubRunnerProperties.StubsMode.LOCAL)
public class LoanApplicationServiceTests {
	. . .
}
----
====

TIP: Use the `REMOTE` `stubsMode` when downloading stubs from an online repository and
`LOCAL` for offline work.

Now, in your integration test, you can receive stubbed versions of HTTP responses or
messages that are expected to be emitted by the collaborator service.

[[getting-started-first-application]]
== Developing Your First Spring Cloud Contract-based Application

This brief tour walks through using Spring Cloud Contract. It consists of the following topics:

* <<getting-started-first-application-producer>>
* <<getting-started-first-application-consumer>>

You can find an even more brief tour
<<getting-started-three-second-tour,here>>.

For the sake of this example, the `Stub Storage` is Nexus/Artifactory.

The following UML diagram shows the relationship of the parts of Spring Cloud Contract:

image::getting-started-three-second.png[Getting started first application]

[[getting-started-first-application-producer]]
=== On the Producer Side

To start working with `Spring Cloud Contract`, you can add the Spring Cloud Contract Verifier
dependency and plugin to your build file, as the following example shows:

====
[source,xml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-server/pom.xml[tags=verifier_test_dependencies,indent=0]
----
====

The following listing shows how to add the plugin, which should go in the build/plugins
portion of the file:

====
[source,xml,indent=0]
----
<plugin>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-contract-maven-plugin</artifactId>
	<version>${spring-cloud-contract.version}</version>
	<extensions>true</extensions>
</plugin>
----
====

[TIP]
====
The easiest way to get started is to go to https://start.spring.io[the Spring Initializr]
and add "`Web`" and "`Contract Verifier`" as dependencies. Doing so pulls in the previously
mentioned dependencies and everything else you need in the `pom.xml` file (except for
setting the base test class, which we cover later in this section). The following image
shows the settings to use in https://start.spring.io[the Spring Initializr]:

image::start_spring_io_dependencies.png[width=800,alt=Spring Initializr with Web and Contract Verifier]
====

Now you can add files with `REST/` messaging contracts
expressed in either Groovy DSL or YAML to the contracts directory, which is set by the
`contractsDslDir` property. By default, it is `$rootDir/src/test/resources/contracts`.
Note that the file name does not matter. You can organize your contracts within this
directory with whatever naming scheme you like.

For the HTTP stubs, a contract defines what kind of response should be returned for a
given request (taking into account the HTTP methods, URLs, headers, status codes, and so
on). The following example shows an HTTP stub contract in both Groovy and YAML:

====
[source,groovy,indent=0,role="primary"]
.groovy
----
package contracts

org.springframework.cloud.contract.spec.Contract.make {
	request {
		method 'PUT'
		url '/fraudcheck'
		body([
			   "client.id": $(regex('[0-9]{10}')),
			   loanAmount: 99999
		])
		headers {
			contentType('application/json')
		}
	}
	response {
		status OK()
		body([
			   fraudCheckStatus: "FRAUD",
			   "rejection.reason": "Amount too high"
		])
		headers {
			contentType('application/json')
		}
	}
}
----

[source,yaml,indent=0,role="secondary"]
.yaml
----
request:
  method: PUT
  url: /fraudcheck
  body:
    "client.id": 1234567890
    loanAmount: 99999
  headers:
    Content-Type: application/json
  matchers:
    body:
      - path: $.['client.id']
        type: by_regex
        value: "[0-9]{10}"
response:
  status: 200
  body:
    fraudCheckStatus: "FRAUD"
    "rejection.reason": "Amount too high"
  headers:
    Content-Type: application/json;charset=UTF-8
----
====

If you need to use messaging, you can define:

* The input and output messages (taking into account from where it
was sent, the message body, and the header).
* The methods that should be called after the message is received.
* The methods that, when called, should trigger a message.

The following example shows a Camel messaging contract:

====
[source,groovy,indent=0,role="primary"]
.groovy
----
include::{verifier_core_path}/src/test/groovy/org/springframework/cloud/contract/verifier/builder/MessagingMethodBodyBuilderSpec.groovy[tags=trigger_method_dsl]
----

[source,yaml,indent=0,role="secondary"]
.yaml
----
include::{verifier_core_path}/src/test/resources/yml/contract_message_scenario1.yml[indent=0]
----
====

Running `./mvnw clean install` automatically generates tests that verify the application
compliance with the added contracts. By default, the generated tests are under
`org.springframework.cloud.contract.verifier.tests.`.

The generated tests may differ, depending on which framework and test type you have set up
in your plugin.

In the next listing, you can find:

- The default test mode for HTTP contracts in `MockMvc`
- A JAX-RS client with the `JAXRS` test mode
- A `WebTestClient`-based test (this is particularly recommended while working with
Reactive, `Web-Flux`-based applications) set with the `WEBTESTCLIENT` test mode

NOTE: You need only one of these test frameworks. MockMvc is the default. To use one
of the other frameworks, add its library to your classpath.

The following listing shows samples for all frameworks:

====
[source,java,indent=0,role="primary"]
.mockmvc
----
@Test
public void validate_shouldMarkClientAsFraud() throws Exception {
    // given:
        MockMvcRequestSpecification request = given()
                .header("Content-Type", "application/vnd.fraud.v1+json")
                .body("{\"client.id\":\"1234567890\",\"loanAmount\":99999}");

    // when:
        ResponseOptions response = given().spec(request)
                .put("/fraudcheck");

    // then:
        assertThat(response.statusCode()).isEqualTo(200);
        assertThat(response.header("Content-Type")).matches("application/vnd.fraud.v1.json.*");
    // and:
        DocumentContext parsedJson = JsonPath.parse(response.getBody().asString());
        assertThatJson(parsedJson).field("['fraudCheckStatus']").matches("[A-Z]{5}");
        assertThatJson(parsedJson).field("['rejection.reason']").isEqualTo("Amount too high");
}
----

[source,java,indent=0,role="secondary"]
.jaxrs
----
@SuppressWarnings("rawtypes")
public class FooTest {
  WebTarget webTarget;

  @Test
  public void validate_() throws Exception {

    // when:
      Response response = webTarget
              .path("/users")
              .queryParam("limit", "10")
              .queryParam("offset", "20")
              .queryParam("filter", "email")
              .queryParam("sort", "name")
              .queryParam("search", "55")
              .queryParam("age", "99")
              .queryParam("name", "Denis.Stepanov")
              .queryParam("email", "bob@email.com")
              .request()
              .build("GET")
              .invoke();
      String responseAsString = response.readEntity(String.class);

    // then:
      assertThat(response.getStatus()).isEqualTo(200);

    // and:
      DocumentContext parsedJson = JsonPath.parse(responseAsString);
      assertThatJson(parsedJson).field("['property1']").isEqualTo("a");
  }

}
----

[source,java,indent=0,role="secondary"]
.webtestclient
----
@Test
	public void validate_shouldRejectABeerIfTooYoung() throws Exception {
		// given:
			WebTestClientRequestSpecification request = given()
					.header("Content-Type", "application/json")
					.body("{\"age\":10}");

		// when:
			WebTestClientResponse response = given().spec(request)
					.post("/check");

		// then:
			assertThat(response.statusCode()).isEqualTo(200);
			assertThat(response.header("Content-Type")).matches("application/json.*");
		// and:
			DocumentContext parsedJson = JsonPath.parse(response.getBody().asString());
			assertThatJson(parsedJson).field("['status']").isEqualTo("NOT_OK");
	}
----
====

As the implementation of the functionalities described by the contracts is not yet
present, the tests fail.

To make them pass, you must add the correct implementation of handling either HTTP
requests or messages. Also, you must add a base test class for auto-generated
tests to the project. This class is extended by all the auto-generated tests and should
contain all the setup necessary information needed to run them (for example,
`RestAssuredMockMvc` controller setup or messaging test setup).

The following example, from `pom.xml`, shows how to specify the base test class:

====
[source,xml,indent=0]
----
<build>
        <plugins>
            <plugin>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-contract-maven-plugin</artifactId>
                <version>2.1.2.RELEASE</version>
                <extensions>true</extensions>
                <configuration>
                    <baseClassForTests>com.example.contractTest.BaseTestClass</baseClassForTests> <1>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
----
<1> The `baseClassForTests` element lets you specify your base test class. It must be a child
of a `configuration` element within `spring-cloud-contract-maven-plugin`.
====

The following example shows a minimal (but functional) base test class:

====
[source,java, indent=0]
----
package com.example.contractTest;

import org.junit.Before;

import io.restassured.module.mockmvc.RestAssuredMockMvc;

public class BaseTestClass {

	@Before
	public void setup() {
		RestAssuredMockMvc.standaloneSetup(new FraudController());
	}
}
----
====

This minimal class really is all you need to get your tests to work. It serves as a
starting place to which the automatically generated tests attach.

Now we can move on to the implementation. For that, we first need a data class, which we
then use in our controller. The following listing shows the data class:

====
[source,java, indent=0]
----
package com.example.Test;

import com.fasterxml.jackson.annotation.JsonProperty;

public class LoanRequest {

	@JsonProperty("client.id")
	private String clientId;

	private Long loanAmount;

	public String getClientId() {
		return clientId;
	}

	public void setClientId(String clientId) {
		this.clientId = clientId;
	}

	public Long getLoanAmount() {
		return loanAmount;
	}

	public void setLoanRequestAmount(Long loanAmount) {
		this.loanAmount = loanAmount;
	}
}
----
====

The preceding class provides an object in which we can store the parameters. Because the
client ID in the contract is called `client.id`, we need to use the
`@JsonProperty("client.id")` parameter to map it to the `clientId` field.

Now we can move along to the controller, which the following listing shows:

====
[source,java, indent=0]
----
package com.example.docTest;

import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class FraudController {

	@PutMapping(value = "/fraudcheck", consumes="application/json", produces="application/json")
	public String check(@RequestBody LoanRequest loanRequest) { <1>

		if (loanRequest.getLoanAmount() > 10000) { <2>
			return "{fraudCheckStatus: FRAUD, rejection.reason: Amount too high}"; <3>
		} else {
			return "{fraudCheckStatus: OK, acceptance.reason: Amount OK}"; <4>
		}
	}
}
----
<1> We map the incoming parameters to a `LoanRequest` object.
<2> We check the requested loan amount to see if it is too much.
<3> If it is too much, we return the JSON (created with a simple string here) that the
test expects.
<4> If we had a test to catch when the amount is allowable, we could match it to this output.
====

The `FraudController` is about as simple as things get. You can do much more, including
logging, validating the client ID, and so on.

Once the implementation and the test base class are in place, the tests pass, and both the
application and the stub artifacts are built and installed in the local Maven repository.
Information about installing the stubs jar to the local repository appears in the logs, as
the following example shows:

====
[source,bash,indent=0]
----
 [INFO] --- spring-cloud-contract-maven-plugin:1.0.0.BUILD-SNAPSHOT:generateStubs (default-generateStubs) @ http-server ---
 [INFO] Building jar: /some/path/http-server/target/http-server-0.0.1-SNAPSHOT-stubs.jar
 [INFO]
 [INFO] --- maven-jar-plugin:2.6:jar (default-jar) @ http-server ---
 [INFO] Building jar: /some/path/http-server/target/http-server-0.0.1-SNAPSHOT.jar
 [INFO]
 [INFO] --- spring-boot-maven-plugin:1.5.5.BUILD-SNAPSHOT:repackage (default) @ http-server ---
 [INFO]
 [INFO] --- maven-install-plugin:2.5.2:install (default-install) @ http-server ---
 [INFO] Installing /some/path/http-server/target/http-server-0.0.1-SNAPSHOT.jar to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT.jar
 [INFO] Installing /some/path/http-server/pom.xml to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT.pom
 [INFO] Installing /some/path/http-server/target/http-server-0.0.1-SNAPSHOT-stubs.jar to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar
----
====

You can now merge the changes and publish both the application and the stub artifacts
in an online repository.

[[getting-started-first-application-consumer]]
=== On the Consumer Side

You can use Spring Cloud Contract Stub Runner in the integration tests to get a running
WireMock instance or messaging route that simulates the actual service.

To get started, add the dependency to `Spring Cloud Contract Stub Runner`, as follows:

====
[source,xml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-client/pom.xml[tags=stub_runner,indent=0]
----
====

You can get the Producer-side stubs installed in your Maven repository in either of two
ways:

* By checking out the Producer side repository and adding contracts and generating the
stubs by running the following commands:
+
====
[source,bash,indent=0]
----
$ cd local-http-server-repo
$ ./mvnw clean install -DskipTests
----
====
NOTE: The tests are skipped because the Producer-side contract implementation is not yet
in place, so the automatically-generated contract tests fail.

* By getting existing producer service stubs from a remote repository. To do so,
pass the stub artifact IDs and artifact repository URL as `Spring Cloud Contract Stub
Runner` properties, as the following example shows:
+
====
[source,yaml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-client/src/test/resources/application-test-repo.yaml[]
----
====

Now you can annotate your test class with `@AutoConfigureStubRunner`. In the annotation,
provide the `group-id` and `artifact-id` for `Spring Cloud Contract Stub Runner` to run
the collaborators' stubs for you, as the following example shows:

====
[source,java, indent=0]
----
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.NONE)
@AutoConfigureStubRunner(ids = {"com.example:http-server-dsl:+:stubs:6565"},
		stubsMode = StubRunnerProperties.StubsMode.LOCAL)
public class LoanApplicationServiceTests {
	. . .
}
----
====

TIP: Use the `REMOTE` `stubsMode` when downloading stubs from an online repository and
`LOCAL` for offline work.

In your integration test, you can receive stubbed versions of HTTP responses or messages
that are expected to be emitted by the collaborator service. You can see entries similar
to the following in the build logs:

====
[source,bash,indent=0]
----
2016-07-19 14:22:25.403  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Desired version is + - will try to resolve the latest version
2016-07-19 14:22:25.438  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Resolved version is 0.0.1-SNAPSHOT
2016-07-19 14:22:25.439  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Resolving artifact com.example:http-server:jar:stubs:0.0.1-SNAPSHOT using remote repositories []
2016-07-19 14:22:25.451  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Resolved artifact com.example:http-server:jar:stubs:0.0.1-SNAPSHOT to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar
2016-07-19 14:22:25.465  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Unpacking stub from JAR [URI: file:/path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar]
2016-07-19 14:22:25.475  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Unpacked file to [/var/folders/0p/xwq47sq106x1_g3dtv6qfm940000gq/T/contracts100276532569594265]
2016-07-19 14:22:27.737  INFO 41050 --- [           main] o.s.c.c.stubrunner.StubRunnerExecutor    : All stubs are now running RunningStubs [namesAndPorts={com.example:http-server:0.0.1-SNAPSHOT:stubs=8080}]
----
====

[[getting-started-cdc]]
== Step-by-step Guide to Consumer Driven Contracts (CDC) with Contracts on the Producer Side

Consider an example of fraud detection and the loan issuance process. The business
scenario is such that we want to issue loans to people but do not want them to steal from
us. The current implementation of our system grants loans to everybody.

Assume that `Loan Issuance` is a client to the `Fraud Detection` server. In the current
sprint, we must develop a new feature: if a client wants to borrow too much money,
we mark the client as a fraud.

Technical remarks

* Fraud Detection has an `artifact-id` of `http-server`.
* Loan Issuance has an `artifact-id` of `http-client`.
* Both have a `group-id` of `com.example`.
* For the sake of this example, the `Stub Storage` is Nexus/Artifactory.

Social remarks

* Both the client and the server development teams need to communicate directly and
discuss changes while going through the process.
* CDC is all about communication.

The server-side code is available under Spring Cloud Contract's repository `samples/standalone/dsl/http-server` path, and the client-side code is available under Spring Cloud Contract's repository `samples/standalone/dsl/http-client` path.

TIP: In this case, the producer owns the contracts. Physically, all the contracts are
in the producer's repository.

[[getting-started-cdc-technical-note]]
=== Technical Note

If you use the SNAPSHOT, Milestone, or Release Candidate versions, you need to add the
following section to your build:

====
[source,xml,indent=0,subs="verbatim,attributes",role="primary"]
.Maven
----
include::{introduction_url}/samples/standalone/dsl/http-server/pom.xml[tags=repos,indent=0]
----
////

////
[source,groovy,indent=0,subs="verbatim,attributes",role="secondary"]
.Gradle
----
include::{introduction_url}/samples/standalone/dsl/http-server/build.gradle[tags=deps_repos,indent=0]
----
====

For simplicity, we use the following acronyms:

- Loan Issuance (LI): The HTTP client
- Fraud Detection (FD): The HTTP server
- SCC: Spring Cloud Contract

[[getting-started-cdc-consumer]]
=== The Consumer Side (Loan Issuance)

As a developer of the Loan Issuance service (a consumer of the Fraud Detection server), you might do the following steps:

. Start doing TDD by writing a test for your feature.
. Write the missing implementation.
. Clone the Fraud Detection service repository locally.
. Define the contract locally in the repository of the fraud detection service.
. Add the Spring Cloud Contract (SCC) plugin.
. Run the integration tests.
. File a pull request.
. Create an initial implementation.
. Take over the pull request.
. Write the missing implementation.
. Deploy your application.
. Work online.

We start with the loan issuance flow, which the following UML diagram shows:

[plantuml, getting-started-cdc-client, png]
----
"Loan\nIssuance"->"Loan\nIssuance": start doing TDD\nby writing a test\nfor your feature
"Loan\nIssuance"->"Loan\nIssuance": write the \nmissing implementation
"Loan\nIssuance"->"Loan\nIssuance": run a test - it fails\ndue to no server running
"Loan\nIssuance"->"Fraud\nDetection\nClone": clone the repository
"Fraud\nDetection\nClone"->"Fraud\nDetection\nClone": add missing dependencies\n& define contracts
"Fraud\nDetection\nClone"->"Fraud\nDetection\nClone": add the SCC plugin
"Fraud\nDetection\nClone"->"FD \nClone Build": install the stubs locally
"FD \nClone Build"->"SCC Plugin \nin FD Clone": generate stubs \nand stubs \nartifact (e.g. stubs-jar)
"SCC Plugin \nin FD Clone"->"FD \nClone Build": stubs and artifacts\ngenerated
"FD \nClone Build"->"Local storage": install the stubs locally
"Local storage"->"FD \nClone Build": stub sucessfully installed
"FD \nClone Build"->"Fraud\nDetection\nClone": build successful
"Loan\nIssuance"->"Loan\nIssuance": add a SCC\nStub Runner\ndependency\nand setup
"Loan\nIssuance"->"LI\nSCC\nStub Runner": start stubs\nof FD from\nlocal storage
"LI\nSCC\nStub Runner"->"Local storage": find stubs of [FD]
"Local storage"->"LI\nSCC\nStub Runner": stubs of [FD] found
"LI\nSCC\nStub Runner"->"FD stub": run stubs of [FD]
"FD stub"->"LI\nSCC\nStub Runner": [FD] stub is running
"LI\nSCC\nStub Runner"->"Loan\nIssuance": stubs running and ready for the test
"Loan\nIssuance"->"Loan\nIssuance": run a test
"Loan\nIssuance"->"FD stub": the test\nsends a request\nto the running stub
"FD stub"->"Loan\nIssuance": stub responds successfuly
"Loan\nIssuance"->"Loan\nIssuance": the test passes successfully
"Loan\nIssuance"->"Fraud\nDetection": send a pull request\nwith the\nsuggested contracts
----

[[getting-started-cdc-consumer-start]]
==== Start Doing TDD by Writing a Test for Your Feature

The following listing shows a test that we might use to check whether a loan amount is too
large:

====
[source,groovy,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-client/src/test/java/com/example/loan/LoanApplicationServiceTests.java[tags=client_tdd,indent=0]
----
====

Assume that you have written a test of your new feature. If a loan application for a big
amount is received, the system should reject that loan application with some description.

[[getting-started-cdc-consumer-write]]
==== Write the Missing Implementation

At some point in time, you need to send a request to the Fraud Detection service. Assume
that you need to send the request containing the ID of the client and the amount the
client wants to borrow. You want to send it to the `/fraudcheck` URL by using the `PUT` method.
To do so, you might use code similar to the following:

====
[source,groovy,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-client/src/main/java/com/example/loan/LoanApplicationService.java[tags=client_call_server,indent=0]
----
====

For simplicity, the port of the Fraud Detection service is set to `8080`, and the
application runs on `8090`.

NOTE: If you start the test at this point, it breaks, because no service currently runs on port
`8080`.

[[getting-started-cdc-consumer-clone]]
==== Clone the Fraud Detection service repository locally

You can start by playing around with the server side contract. To do so, you must first
clone it, by running the following command:

====
[source,bash,indent=0]
----
$ git clone https://your-git-server.com/server-side.git local-http-server-repo
----
====

[[getting-started-cdc-consumer-define]]
==== Define the Contract Locally in the Repository of the Fraud Detection Service

As a consumer, you need to define what exactly you want to achieve. You need to formulate
your expectations. To do so, write the following contract:

IMPORTANT: Place the contract in the `src/test/resources/contracts/fraud` folder. The `fraud` folder
is important because the producer's test base class name references that folder.

The following example shows our contract, in both Groovy and YAML:

====
[source,groovy,indent=0,role="primary"]
.groovy
----
include::{introduction_url}/samples/standalone/dsl/http-server/src/test/resources/contracts/fraud/shouldMarkClientAsFraud.groovy[]
----
////

////
[source,yaml,indent=0,role="secondary"]
.yaml
----
include::{introduction_url}/samples/standalone/dsl/http-server/src/test/resources/contracts/yml/fraud/shouldMarkClientAsFraud.yml[]
----
====

The YML contract is quite straightforward. However, when you take a look at the contract
written with a statically typed Groovy DSL, you might wonder what the
`value(client(...), server(...))` parts are. By using this notation, Spring Cloud
Contract lets you define parts of a JSON block, a URL, or other structure that is dynamic. In the case
of an identifier or a timestamp, you need not hardcode a value. You want to allow some
different ranges of values. To enable ranges of values, you can set regular expressions
that match those values for the consumer side. You can provide the body by means of either
a map notation or a String with interpolations. We highly recommend using the map notation.

TIP: To set up contracts, you must understand the map notation. See the
https://groovy-lang.org/json.html[Groovy docs regarding JSON].

The previously shown contract is an agreement between two sides that:

* If an HTTP request is sent with all of:
** A `PUT` method on the `/fraudcheck` endpoint
** A JSON body with a `client.id` that matches the regular expression `[0-9]{10}` and
`loanAmount` equal to `99999`
** A `Content-Type` header with a value of `application/vnd.fraud.v1+json`
* Then an HTTP response is sent to the consumer that
** Has status `200`
** Contains a JSON body with the `fraudCheckStatus` field containing a value of `FRAUD` and
the `rejectionReason` field having a value of `Amount too high`
** Has a `Content-Type` header with a value of `application/vnd.fraud.v1+json`

Once you are ready to check the API in practice in the integration tests, you need to
install the stubs locally.

[[getting-started-cdc-consumer-add]]
==== Add the Spring Cloud Contract Verifier Plugin

We can add either a Maven or a Gradle plugin. In this example, we show how to add Maven.
First, we add the `Spring Cloud Contract` BOM, as the following example shows:

====
[source,xml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-server/pom.xml[tags=contract_bom,indent=0]
----
====

Next, add the `Spring Cloud Contract Verifier` Maven plugin, as the following example shows:

====
[source,xml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-server/pom.xml[tags=contract_maven_plugin,indent=0]
----
====

Since the plugin was added, you get the `Spring Cloud Contract Verifier` features, which,
from the provided contracts:

- Generate and run tests
- Produce and install stubs

You do not want to generate tests, since you, as the consumer, want only to play with the
stubs. You need to skip the test generation and invokation. To do so, run the following commands:

====
[source,bash,indent=0]
----
$ cd local-http-server-repo
$ ./mvnw clean install -DskipTests
----
====

Once you run those commands, you should you see something like the following content in the logs:

====
[source,bash,indent=0]
----
[INFO] --- spring-cloud-contract-maven-plugin:1.0.0.BUILD-SNAPSHOT:generateStubs (default-generateStubs) @ http-server ---
[INFO] Building jar: /some/path/http-server/target/http-server-0.0.1-SNAPSHOT-stubs.jar
[INFO]
[INFO] --- maven-jar-plugin:2.6:jar (default-jar) @ http-server ---
[INFO] Building jar: /some/path/http-server/target/http-server-0.0.1-SNAPSHOT.jar
[INFO]
[INFO] --- spring-boot-maven-plugin:1.5.5.BUILD-SNAPSHOT:repackage (default) @ http-server ---
[INFO]
[INFO] --- maven-install-plugin:2.5.2:install (default-install) @ http-server ---
[INFO] Installing /some/path/http-server/target/http-server-0.0.1-SNAPSHOT.jar to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT.jar
[INFO] Installing /some/path/http-server/pom.xml to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT.pom
[INFO] Installing /some/path/http-server/target/http-server-0.0.1-SNAPSHOT-stubs.jar to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar
----
====

The following line is extremely important:

====
[source,bash,indent=0]
----
[INFO] Installing /some/path/http-server/target/http-server-0.0.1-SNAPSHOT-stubs.jar to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar
----
====

It confirms that the stubs of the `http-server` have been installed in the local
repository.

[[getting-started-cdc-consumer-run]]
==== Running the Integration Tests

In order to profit from the Spring Cloud Contract Stub Runner functionality of automatic
stub downloading, you must do the following in your consumer side project (`Loan
Application service`):

. Add the `Spring Cloud Contract` BOM, as follows:
+
====
[source,xml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-client/pom.xml[tags=contract_bom,indent=0]
----
====

. Add the dependency to `Spring Cloud Contract Stub Runner`, as follows:
+
====
[source,xml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-client/pom.xml[tags=stub_runner,indent=0]
----
====

. Annotate your test class with `@AutoConfigureStubRunner`. In the annotation, provide the
`group-id` and `artifact-id` for the Stub Runner to download the stubs of your
collaborators.
+
====
[source,groovy,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-client/src/test/java/com/example/loan/LoanApplicationServiceTests.java[tags=autoconfigure_stubrunner,indent=0]
----
====

.  (Optional) Because you are playing with the collaborators offline, you
can also provide the offline work switch (`StubRunnerProperties.StubsMode.LOCAL`).

Now, when you run your tests, you see something like the following output in the logs:

====
[source,bash,indent=0]
----
2016-07-19 14:22:25.403  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Desired version is + - will try to resolve the latest version
2016-07-19 14:22:25.438  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Resolved version is 0.0.1-SNAPSHOT
2016-07-19 14:22:25.439  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Resolving artifact com.example:http-server:jar:stubs:0.0.1-SNAPSHOT using remote repositories []
2016-07-19 14:22:25.451  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Resolved artifact com.example:http-server:jar:stubs:0.0.1-SNAPSHOT to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar
2016-07-19 14:22:25.465  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Unpacking stub from JAR [URI: file:/path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar]
2016-07-19 14:22:25.475  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Unpacked file to [/var/folders/0p/xwq47sq106x1_g3dtv6qfm940000gq/T/contracts100276532569594265]
2016-07-19 14:22:27.737  INFO 41050 --- [           main] o.s.c.c.stubrunner.StubRunnerExecutor    : All stubs are now running RunningStubs [namesAndPorts={com.example:http-server:0.0.1-SNAPSHOT:stubs=8080}]
----
====

This output means that Stub Runner has found your stubs and started a server for your application
with a group ID of `com.example` and an artifact ID of `http-server` with version `0.0.1-SNAPSHOT` of
the stubs and with the `stubs` classifier on port `8080`.

[[getting-started-cdc-consumer-file]]
==== Filing a Pull Request

What you have done until now is an iterative process. You can play around with the
contract, install it locally, and work on the consumer side until the contract works as
you wish.

Once you are satisfied with the results and the test passes, you can publish a pull request to
the server side. Currently, the consumer side work is done.

[[getting-started-cdc-producer]]
=== The Producer Side (Fraud Detection server)

As a developer of the Fraud Detection server (a server to the Loan Issuance service), you
might want to:

- Take over the pull request
- Write the missing implementation
- Deploy the application

The following UML diagram shows the fraud detection flow:

[plantuml, getting-started-cdc-server, png]
----
"Fraud\nDetection"->"Fraud\nDetection": take over the\n pull request
"Fraud\nDetection"->"Fraud\nDetection": setup\nSpring Cloud\nContract plugin
"Fraud\nDetection"->"Fraud\nDetection\nBuild": run the build
"Fraud\nDetection\nBuild"->"SCC Plugin": generate tests\nstubs \nand stubs artifact \n(e.g. stubs-jar)
"SCC Plugin"->"Fraud\nDetection\nBuild": tests and stubs generated
"Fraud\nDetection\nBuild"->"Fraud\nDetection\nBuild": run tests
"Fraud\nDetection\nBuild"->"Fraud\nDetection": generated tests failed!
"Fraud\nDetection"->"Fraud\nDetection": setup\nbase classes\nfor contract tests
"Fraud\nDetection"->"Fraud\nDetection\nBuild": run the build
"Fraud\nDetection\nBuild"->"SCC Plugin": generate tests\nstubs \nand stubs artifact \n(e.g. stubs-jar)
"SCC Plugin"->"Fraud\nDetection\nBuild": tests and stubs generated
"Fraud\nDetection\nBuild"->"Fraud\nDetection\nBuild": run tests
"Fraud\nDetection\nBuild"->"Fraud\nDetection": all the tests passed!
"Fraud\nDetection"->"Fraud\nDetection": commit and push changes
"Fraud\nDetection"->"CI": commit pushed!\nTriggers the build
"CI"->"Stub Storage": build successful,\nupload artifacts
----

[[getting-started-cdc-producer-pr]]
==== Taking over the Pull Request

As a reminder, the following listing shows the initial implementation:

====
[source,java,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-server/src/main/java/com/example/fraud/FraudDetectionController.java[tags=server_api,indent=0]
include::{introduction_url}/samples/standalone/dsl/http-server/src/main/java/com/example/fraud/FraudDetectionController.java[tags=initial_impl,indent=0]
}
----
====

Then you can run the following commands:

====
[source,bash,indent=0]
----
$ git checkout -b contract-change-pr master
$ git pull https://your-git-server.com/server-side-fork.git contract-change-pr
----
====

You must add the dependencies needed by the autogenerated tests, as follows:

====
[source,xml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-server/pom.xml[tags=verifier_test_dependencies,indent=0]
----
====

In the configuration of the Maven plugin, you must pass the `packageWithBaseClasses` property, as follows:

====
[source,xml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-server/pom.xml[tags=contract_maven_plugin,indent=0]
----
====

IMPORTANT: This example uses "`convention-based`" naming by setting the
`packageWithBaseClasses` property. Doing so means that the two last packages combine to
make the name of the base test class. In our case, the contracts were placed under
`src/test/resources/contracts/fraud`. Since you do not have two packages starting from
the `contracts` folder, pick only one, which should be `fraud`. Add the `Base` suffix and
capitalize `fraud`. That gives you the `FraudBase` test class name.

All the generated tests extend that class. Over there, you can set up your Spring Context
or whatever is necessary. In this case, you should use https://github.com/rest-assured/rest-assured[Rest Assured MVC] to
start the server side `FraudDetectionController`. The following listing shows the
`FraudBase` class:

====
[source,java,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-server/src/test/java/com/example/fraud/FraudBase.java[]
----
====

Now, if you run the `./mvnw clean install`, you get something like the following output:

====
[source,bash,indent=0]
----
Results :

Tests in error:
  ContractVerifierTest.validate_shouldMarkClientAsFraud:32 » IllegalState Parsed...
----
====

This error occurs because you have a new contract from which a test was generated, and it
failed since you have not implemented the feature. The auto-generated test would look
like the following test method:

====
[source,java,indent=0]
----
@Test
public void validate_shouldMarkClientAsFraud() throws Exception {
    // given:
        MockMvcRequestSpecification request = given()
                .header("Content-Type", "application/vnd.fraud.v1+json")
                .body("{\"client.id\":\"1234567890\",\"loanAmount\":99999}");

    // when:
        ResponseOptions response = given().spec(request)
                .put("/fraudcheck");

    // then:
        assertThat(response.statusCode()).isEqualTo(200);
        assertThat(response.header("Content-Type")).matches("application/vnd.fraud.v1.json.*");
    // and:
        DocumentContext parsedJson = JsonPath.parse(response.getBody().asString());
        assertThatJson(parsedJson).field("['fraudCheckStatus']").matches("[A-Z]{5}");
        assertThatJson(parsedJson).field("['rejection.reason']").isEqualTo("Amount too high");
}
----
====

If you used the Groovy DSL, you can see that all the `producer()` parts of the Contract that were present in the
`value(consumer(...), producer(...))` blocks got injected into the test.
If you use YAML, the same applies for the `matchers` sections of the `response`.

Note that, on the producer side, you are also doing TDD. The expectations are expressed
in the form of a test. This test sends a request to our own application with the URL,
headers, and body defined in the contract. It also expects precisely defined values
in the response. In other words, you have the `red` part of `red`, `green`, and
`refactor`. It is time to convert the `red` into the `green`.

[[getting-started-cdc-producer-impl]]
==== Write the Missing Implementation

Because you know the expected input and expected output, you can write the missing
implementation as follows:

====
[source,java,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-server/src/main/java/com/example/fraud/FraudDetectionController.java[tags=server_api,indent=0]
include::{introduction_url}/samples/standalone/dsl/http-server/src/main/java/com/example/fraud/FraudDetectionController.java[tags=new_impl,indent=0]
include::{introduction_url}/samples/standalone/dsl/http-server/src/main/java/com/example/fraud/FraudDetectionController.java[tags=initial_impl,indent=0]
}
----
====

When you run `./mvnw clean install` again, the tests pass. Since the Spring Cloud
Contract Verifier plugin adds the tests to the `generated-test-sources`, you can
actually run those tests from your IDE.

[[getting-started-cdc-producer-deploy]]
==== Deploying Your Application

Once you finish your work, you can deploy your changes. To do so, you must first merge the
branch by running the following commands:

====
[source,bash,indent=0]
----
$ git checkout master
$ git merge --no-ff contract-change-pr
$ git push origin master
----
====

Your CI might run a command such as `./mvnw clean deploy`, which would publish both the
application and the stub artifacts.

[[getting-started-cdc-consumer-final]]
=== Consumer Side (Loan Issuance), Final Step

As a developer of the loan issuance service (a consumer of the Fraud Detection server), you need to:

- Merge our feature branch to `master`
- Switch to online mode of working

The following UML diagram shows the final state of the process:

[plantuml, getting-started-cdc-client-final, png]
----
"Loan\nIssuance"->"Loan\nIssuance": merge the\nfeature branch\nto master branch
"Loan\nIssuance"->"Loan\nIssuance": setup SCC Stub Runner\nto fetch stubs\nfrom Stub Storage
"Loan\nIssuance"->"LI\nSCC\nStub Runner": start stubs\nof FD from\nStub Storage
"LI\nSCC\nStub Runner"->"Stub Storage": find stubs of [FD]
"Stub Storage"->"LI\nSCC\nStub Runner": stubs of [FD] found
"LI\nSCC\nStub Runner"->"FD stub": run stubs of [FD]
"FD stub"->"LI\nSCC\nStub Runner": [FD] stub is running
"LI\nSCC\nStub Runner"->"Loan\nIssuance": stubs running and ready for the test
"Loan\nIssuance"->"Loan\nIssuance": run a test
"Loan\nIssuance"->"FD stub": the test\nsends a request\nto the running stub
"FD stub"->"Loan\nIssuance": stub responds successfuly
"Loan\nIssuance"->"Loan\nIssuance": the test passes successfully
----

[[getting-started-cdc-consumer-final-merge]]
==== Merging a Branch to Master

The following commands show one way to merge a branch into master with Git:

====
[source,bash,indent=0]
----
$ git checkout master
$ git merge --no-ff contract-change-pr
----
====

[[getting-started-cdc-consumer-final-online]]
==== Working Online

Now you can disable the offline work for Spring Cloud Contract Stub Runner and indicate
where the repository with your stubs is located. At this moment, the stubs of the server
side are automatically downloaded from Nexus/Artifactory. You can set the value of
`stubsMode` to `REMOTE`. The following code shows an example of
achieving the same thing by changing the properties:

====
[source,yaml,indent=0]
----
include::{introduction_url}/samples/standalone/dsl/http-client/src/test/resources/application-test-repo.yaml[]
----
====

That's it. You have finished the tutorial.

[[getting-started-whats-next]]
== Next Steps

Hopefully, this section provided some of the {project-full-name} basics and got you on your way
to writing your own applications. If you are a task-oriented type of developer, you might
want to jump over to https://spring.io and check out some
https://spring.io/guides/[getting started] guides that solve specific "`How do I do that
with Spring?`" problems. We also have {project-full-name}-specific
"`<<howto.adoc#howto, how-to>>`" reference documentation.

Otherwise, the next logical step is to read <<using.adoc#using, Using {project-full-name}>>. If
you are really impatient, you could also jump ahead and read about
<<project-features.adoc#project-features, {project-full-name} features>>.

In addition, you can check out the following videos:

- "Consumer Driven Contracts and Your Microservice Architecture" by Olga Maciaszek-Sharma and Marcin Grzejszczak

video::pDkC_00hhvA[youtube,width=640,height=480]

- "Contract Tests in the Enterprise" by Marcin Grzejszczak

video::ZyHG-VOzPZg[youtube,width=640,height=480]

- "Why Contract Tests Matter?" by Marcin Grzejszczak

video::TvpkZu1e2Dc[youtube,start=6262,width=640,height=480]

You can find the default project samples at
https://github.com/spring-cloud-samples/spring-cloud-contract-samples[samples].
