### Question:
DefaultCommandManager implements CommandManager { @NotNull @Override public @UnmodifiableView Collection<CommandContainer> getCommands() { return Collections.unmodifiableCollection(this.commands); }  @Override @NotNull CommandManager registerCommand(@NotNull Command command, @NotNull String description, @NotNull List<String> aliases); @Override void unregisterCommand(@NotNull CommandContainer command); @Override void unregisterCommand(@NotNull String... aliases); @NotNull @Override Optional<CommandContainer> getCommand(@NotNull String anyAlias); @NotNull @Override @UnmodifiableView Collection<CommandContainer> getCommands(); @Override boolean process(@NotNull String commandLine, @NotNull CommandSender commandSender); @NotNull @Override List<String> suggest(@NotNull String commandLine, @NotNull CommandSender commandSender);  }### Answer:
@Test @Order(3) void testCommandAllCommands() { Assertions.assertEquals(1, this.commandManager.getCommands().size()); Assertions.assertThrows(UnsupportedOperationException.class, () -> this.commandManager.getCommands().add( new DefaultCommandContainer(Collections.singletonList("v"), "test", new TestCommand()) )); }