Client client = createMock(Client.class);
PrivateKey privateKey = createMock(PrivateKey.class);
ClientForGroup fn = new ClientForGroup(chefApi);
expect(chefApi.listClients()).andReturn(
ImmutableSet.<String> of("foo-client-00", "foo-client-01", "foo-client-02"));
expect(chefApi.createClient("foo-client-03")).andReturn(client);
expect(client.getPrivateKey()).andReturn(privateKey);
replay(client);