How to increase the Code Coverage in 2 easy steps

As a developer you come to the point in time where a manager asks you to have at least 80% Code Coverage in your code.

 
Photo Credit: Sam Foster

All managers love to see numbers, especially big increasing numbers.
I love big numbers too!

The nasty ones of you might ask a question back:

• “Why do you want those numbers?” or
• “What do you need those numbers for?” or
• “Who are you going to show them?”

But let’s not do a “Root Cause Analysis” here and just solve the symptom.

Lets look at this project and the Code Coverage for it.

Figure: Before: 74.83 % Code Coverage

 

Here is how you can increase your code coverage in 2 easy steps.

Copy the following into your production code

// Call this method something important. 
// Use words like: Manager, Proxy, Controller, Command, Dispatcher, Broker, Container …
public bool IsMessageProxyControllerManager()
{
    //Repeat more often to increase Code Coverage
    CreateNewImplementation(); 
    CreateNewImplementation();
    CreateNewImplementation();
    CreateNewImplementation(); 
    CreateNewImplementation();
    CreateNewImplementation();
    CreateNewImplementation();
    CreateNewImplementation();
    CreateNewImplementation();
    CreateNewImplementation();
    CreateNewImplementation();
    CreateNewImplementation();
    CreateNewImplementation();
    CreateNewImplementation(); 
    CreateNewImplementation();
    CreateNewImplementation();
    CreateNewImplementation(); 
    CreateNewImplementation();
    return true;
}

// Rename this to something important. 
// Mix 2 words from: Invoke, Caller, Fetch, Request, Factory, Synchronizer, Shepherd, Coordinator 
// 
// If you cant come up with something use https://github.com/ab9/classnamer 
public void CreateNewImplementation()
{
    
}

Copy the following in your test code

[TestMethod]
public void GivenANewInstance_MessageProxyControllerManager_ExpectAPositiveAnswer()
{
    var c = new ClassWhereYouCopiedThe2Methods();  // Change this
    var result = c.IsMessageProxyControllerManager();
    Assert.IsTrue(result);
}

 

Run the Code Coverage Tester again, and Voila!

Figure: After: Increased Code Coverage from 74% to 79% Code Coverage

 

Think about what Code Coverage really tells you

• Does it really measure code lines tested?
• Or does it measure code lines executed?
• What does that number tell you?
• Is it of value to you? To a manager?
• Is 80% Code Coverage a good goal?

 

Now… what are you going to tell your manager?