Does it make sense to have two packages in the same directory?

Question

I have a project that provides a library (exports some funcs) and also must provide a command-line interface (there must be an executable file).

Example of directory

Answer 1

In most cases, no. However, there is an exception for unit tests.

Working Example:

Here are 2 different packages (mypackage and mypackage_test) in 1 directory (mypackage). The compiler will not complain about this.

mypackage folder:

mypackage/
  foo.go
  foo_test.go

mypackage/foo.go:

package mypackage

func Add(a int, b int) int {
    return a + b
}

mypackage/foo_test.go:

package mypackage_test

// Unit tests...

Rules:

1. The 2 packages must have the following names:

   • NameOfDirectory.
   • NameOfDirectory + _test.

2. The names of the files in the _test package must end with _test.go

If you're receiving a confusing compiler error along the lines of found packages "foo" and "bar", you've probably broken one or more of these rules.