Gaining insights through code coverage

Code coverage is a tool in Xcode that is used to gain insights into how much of your code you are testing with your test suite. It tells you exactly which parts of your code were executed during a test and which parts of your code were not. This is extremely useful because you can take focused action based on the information provided by code coverage.

Follow these steps to enable the code coverage functionality:

1. To enable Code Coverage, open the scheme editor through the (Product | Scheme) menu:

   Figure 19.2 – Editing scheme

2. Select Test action and make sure the Gather coverage checkbox on the Options tab is checked:

   Figure 19.3 – Gather coverage option

   Tip

   You can also press Command + < to open the scheme editor quickly.

3. After doing this, close the scheme editor and run your tests.

   This time, Xcode will monitor which parts of your code were executed during this test, and which parts weren't. This information...