@Test
public void inputFileFromRelativePath() {

  assertThat(groovyFileSystem.sourceInputFileFromRelativePath(null)).isNull();
  fileSystem.add(new DefaultInputFile("", "fake1.file"));
  assertThat(groovyFileSystem.sourceInputFileFromRelativePath("fake1.file")).isNull();
  fileSystem.add(new DefaultInputFile("", "fake2.file").setType(Type.MAIN).setLanguage(Groovy.KEY));
  assertThat(groovyFileSystem.sourceInputFileFromRelativePath("fake2.file")).isNotNull();
  fileSystem.add(new DefaultInputFile("", "org/sample/foo/fake3.file").setType(Type.MAIN).setLanguage(Groovy.KEY));
  assertThat(groovyFileSystem.sourceInputFileFromRelativePath("foo/fake3.file")).isNotNull();
}