Hands-On Dependency Injection in Go

When the magic fades

Earlier in the book, I challenged you to examine each method of DI presented in the book with a critical eye. With that in mind, we should consider the potential costs of monkey patching.

Data races—We saw in our examples that monkey patching is the process of replacing a global variable with a copy that performs in the way we need it to for a particular test. And that is perhaps the biggest problem. Swapping something global, and therefore shared, for something specific causes a data race on that variable.

To understand this data race a little more, we need to understand how Go runs tests. By default, tests within a package are executed sequentially. We can reduce our test execution time by marking our tests with t.Parallel() ...