Redis client testing

I am a TDD guy. If I don't write some test cases, even for simple stuff, I feel uneasy. So, when I wrote the unique and the shared Radis wrappers for the previous posts, I let some (very basic) tests drive my code development. I guess it could be useful to have a look to them. The full C++ code is on github, you would need Google Test, Redis and its hiredis plugin, and a C++11-compliant compiler to build it. It won't be difficult to refactor the code for a different test framework (better if xUnit-based), and for a less modern C++ compiler, using Boost (or another library) for smart pointer support.

Firstly, I have written a tiny wrapper class to Google Test, just to make the code less messy, in Tester.h:
class Tester
    Tester(int argc, char** argv) { testing::InitGoogleTest(&argc, argv); } // 1

    int run() { return RUN_ALL_TESTS(); } // 2
1. Before running any test, we should initialize the environment. What a better place than a constructor to do that?
2. I am happy with a very basic usage of Google Test, I would simply run all the tests.

Then I have written a simple main function, that creates an object Tester, and run it:
Tester(argc, argv).run();
I don't even use the return value from run(), I rely on the output generated by Google Test to let the user understand how the testing behaved.

Finally, I put in a source file all the tests I want to be performed. Here are some of them:
TEST(TestConnectShared, BadPort) // 1
    TTR::SharedRedis redis(1234); // 2
    ASSERT_FALSE(redis.isConnected()); // 3

TEST(TestConnectShared, Vanilla) // 4
    TTR::SharedRedis redis;

TEST(TestCopyShared, Copy) // 5
    TTR::SharedRedis redis;
    TTR::SharedRedis r2 = redis;
1. The TEST() macro requires a test case name (here is TestConnectShared) and a test function name (BadPort). These names should make clear what we are testing here. In this case, I want to check the shared Redis connection behavior when I pass a wrong port number. Notice that the prerequisite is that the Redis server is up and running on localhost, default port.
2. I have put SharedRedis in a namespace named TTR (short for ThisThread Redis), that's way I use that prefix here.
3. I expect isConnected() to return false, so I assert it. If, unexpectedly, I get a valid connection to Redis, this test would fail.
4. The vanilla test on a shared Redis connection would try to create a default connection to Redis. If isConnected() does not return true, I should assume the test has failed.
5. A simple test to check if I can actually copy a shared Redis connection, and if the copy is still connected to Redis.

If you run those tests when a Redis server is not running on your localhost (and accepting connections on its default port), you should expect a number of failures. Actually, it would (wrongly) succeed only the tests expecting a failure, as the shown TestConnectShared-BadPort. Otherwise I would expect an all green lights scenario.

No comments:

Post a Comment