Suppose I have a package like this:

package my_package

var feature = os.Getenv("FEATURE_NAME")

func whatever(input string) {
    if input == feature {
        doSomething()
    } else {
        doSomethingElse()
    }
}

Where the feature variable may be used several more times.

While testing, I’d like to stub the environment:

func TestSomething(t *testing.T) {
    t.Setenv("FEATURE_NAME", "a_feature")
    // run assertions
}

However, t.Setenv will not work here, because the feature assignment will be evaluated before stubbing the environment in the test.

What would be the best solution for this scenario? I can think of:

• creating a function to lazy-load the env variable
• initialize the variable inside the function

Are there better options?