### Question:
StackManager { public Map<String, List<StackInfo>> getStacksByName() { Map<String, List<StackInfo>> stacks = new HashMap<>(); for (StackInfo stack: stackMap.values()) { List<StackInfo> list = stacks.get(stack.getName()); if (list == null) { list = new ArrayList<>(); stacks.put(stack.getName(), list); } list.add(stack); } return stacks; } @AssistedInject  StackManager(@Assisted("stackRoot") File stackRoot,
      @Assisted("commonServicesRoot") @Nullable File commonServicesRoot,
      @Assisted("extensionRoot") @Nullable File extensionRoot,
      @Assisted OsFamily osFamily, @Assisted boolean validate,
      MetainfoDAO metaInfoDAO, ActionMetadata actionMetadata, StackDAO stackDao,
      ExtensionDAO extensionDao, ExtensionLinkDAO linkDao, AmbariManagementHelper helper); StackInfo getStack(String name, String version); Collection<StackInfo> getStacks(String name); Map<String, List<StackInfo>> getStacksByName(); Collection<StackInfo> getStacks(); ExtensionInfo getExtension(String name, String version); Collection<ExtensionInfo> getExtensions(String name); Collection<ExtensionInfo> getExtensions(); boolean haveAllRepoUrlsBeenResolved(); static Validator getPropertySchemaValidator(); static void validateAllPropertyXmlsInFolderRecursively(File stackRoot, Validator validator); void linkStackToExtension(StackInfo stack, ExtensionInfo extension); void unlinkStackAndExtension(StackInfo stack, ExtensionInfo extension); static final String PROPERTY_SCHEMA_PATH; static String PATH_DELIMITER; static final String COMMON_SERVICES; static final String EXTENSIONS; static final String METAINFO_FILE_NAME; }### Answer:
@Test public void testGetStacksByName() { Collection<StackInfo> stacks = stackManager.getStacks("HDP"); assertEquals(17, stacks.size()); stacks = stackManager.getStacks("OTHER"); assertEquals(2, stacks.size()); }