Chapter 2, Unit Testing Essentials

1. In Go, a module is a collection of packages that should be built and released together. A package is a collection of Go files that must be built together. A module is specified by a go.mod file, while a package is specified by the package declaration at the top of the source file.
2. The additional test package is a package that matches the name of the source package with the _test suffix added. The additional test package provides isolation between test code and source code, preventing brittle tests and allowing developers to see the integrations with their packages.
3. Test signatures have only a few requirements:
   1. The test name must begin with the word Test
   2. Any other name that follows the Test must also be capitalized
   3. There must only be one parameter of the *testing.T type and no return type
4. Subtests are tests that run within an enclosing test. They are created by passing a name and corresponding function to the t.Run method on the enclosing...