### Question:
JjtreeProgramInvoker extends AbstractProgramInvoker { @Override public String supportedSuffix() { return SUPPORTED_FILE_SUFFIX; } JjtreeProgramInvoker(Project project, Configuration classpath, File tempOutputDirectory); @Override ProgramArguments augmentArguments(File inputDirectory, RelativePath inputRelativePath, ProgramArguments arguments); @Override String getProgramName(); @Override String supportedSuffix(); static final String SUPPORTED_FILE_SUFFIX; }### Answer:
@Test public void supportsJjtreeFiles() { String supportedSuffix = programInvoker.supportedSuffix(); assertThat(supportedSuffix, is(equalTo(".jjt"))); }