### Question:
PackagingProviderConverter implements Converter<PackagingProvider> { public boolean getAllPossibleValues(final List<Completion> completions, final Class<?> targetType, final String existingData, final String optionContext, final MethodTarget target) { for (final PackagingProvider packagingProvider : packagingProviderRegistry .getAllPackagingProviders()) { completions.add(new Completion(packagingProvider.getId().toUpperCase())); } return true; }  PackagingProvider convertFromText(final String value, final Class<?> targetType,
      final String optionContext); boolean getAllPossibleValues(final List<Completion> completions,
      final Class<?> targetType, final String existingData, final String optionContext,
      final MethodTarget target); boolean supports(final Class<?> type, final String optionContext);  }### Answer:
@Test public void testGetAllPossibleValues() { final PackagingProvider[] providers = {mockCoreJarPackaging, mockCustomJarPackaging, mockWarPackaging}; when(mockPackagingProviderRegistry.getAllPackagingProviders()).thenReturn( Arrays.asList(providers)); final List<Completion> expectedCompletions = new ArrayList<Completion>(); for (final PackagingProvider provider : providers) { expectedCompletions.add(new Completion(provider.getId().toUpperCase())); } final List<Completion> completions = new ArrayList<Completion>(); final boolean addSpace = converter.getAllPossibleValues(completions, PackagingProvider.class, "ignored", null, null); assertTrue(addSpace); assertEquals(expectedCompletions.size(), completions.size()); assertTrue("Expected " + expectedCompletions + " but was " + completions, completions.containsAll(expectedCompletions)); }