Using Core

Installing

To install Diferencia Java JUnit you need to add JUnit 4 and Diferencia JUnit dependencies on your build tool.

For now Diferencia is released in jcenter but in near future will be released in Maven central as well.

pom.xml

<repositories>
    <repository>
        <snapshots>
            <enabled>false</enabled>
        </snapshots>
        <id>central</id>
        <name>bintray</name>
        <url>https://jcenter.bintray.com</url>
    </repository>
</repositories>

Maven

pom.xml

<dependency>
    <groupId>com.lordofthejars.diferencia</groupId>
    <artifactId>diferencia-java-junit</artifactId>
    <version>${version}</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
    <scope>test</scope>
</dependency>

Gradle

build.gradle

testCompile "com.lordofthejars.diferencia:diferencia-java-junit:${version}"
testCompile "junit:junit:4.12"

Code Example

The JUnit Rule class to be used is com.lordofthejars.diferencia.junit.DiferenciaRule which is the one responsible for managing the lifecycle of Diferencia and provides methods to get Diferencia clients.

ExampleTest.java

@ClassRule (1)
public static DiferenciaRule diferenciaRule =
    new DiferenciaRule("http://now.httpbin.org/",
                       "http://now.httpbin.org/"); (2)

@Test
public void should_use_diferencia_to_detect_any_possible_regression()
      throws IOException {
    final String diferenciaUrl = diferenciaRule.getDiferenciaUrl(); (3)
    final Response response = sendRequest(diferenciaUrl, "/");
    assertThat(response.code()).isEqualTo(HTTP_PRECON_FAILED); (4)
}

1	`ClassRule` for better performance.
2	Defines and configures Diferencia. You can also use `DiferenciaConfiguration` object as parameter.
3	Gets URL to send requests.
4	In this case both responses are different so they should fail.

About sending requests

sendRequest is a helper method created in the test to send request to Diferencia.

In this case it is using OkHttp to send to the Diferencia proxy a GET request to / path. Internally Diferencia will duplicate this call to the primary and to the candidate, compare both responses and send back the result.

Of course you can use any other HttpClient to validate the compatibility such as REST-assured.