§Testing your application

Test source files must be placed in your application’s test folder. You can run tests from the Play console using the test (run all tests) and test-only (run one test class: test-only my.namespace.MySpec) tasks.

§Using JUnit

The default way to test a Play application is with JUnit.

package test;

import org.junit.*;

import play.mvc.*;
import play.test.*;
import play.libs.F.*;

import static play.test.Helpers.*;
import static org.fest.assertions.Assertions.*;

public class SimpleTest {

    @Test 
    public void simpleCheck() {
        int a = 1 + 1;
        assertThat(a).isEqualTo(2);
    }

}

A new process is forked each time test or test-only is run. The new process uses default JVM settings. Custom settings can be added to build.sbt. For example:

javaOptions in Test ++= Seq(
  "-Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=9998",
  "-Xms512M",
  "-Xmx1536M",
  "-Xss1M",
  "-XX:MaxPermSize=384M"
)

§Running in a fake application

If the code you want to test depends on a running application, you can easily create a FakeApplication on the fly:

@Test
public void findById() {
  running(fakeApplication(), new Runnable() {
    public void run() {
      Computer macintosh = Computer.find.byId(21l);
      assertThat(macintosh.name).isEqualTo("Macintosh");
      assertThat(formatted(macintosh.introduced)).isEqualTo("1984-01-24");
    }
  });
}

You can also pass (or override) additional application configuration, or mock any plugin. For example to create a FakeApplication using a default in-memory database:

fakeApplication(inMemoryDatabase())

Applications using Ebean ORM may be written to rely on Play’s automatic getter/setter generation. Play also rewrites field accesses to use the generated getters/setters. Ebean relies on calls to the setters to do dirty checking. In order to use these patterns in JUnit tests, you will need to enable Play’s field access rewriting in test by adding the following to build.sbt:

compile in Test <<= PostCompile(Test)

Next: Writing functional tests