package stub

import "go.abhg.dev/testing/stub"

Package stub provides helper functions to replace global variables for testing, and restore them afterwards.

Index

• func Func(fnptr any, rets ...any) (restore func())
• func Value(ptr *T, value T) (restore func())

Functions

func Func

func Func(fnptr any, rets ...any) (restore func())

Func replaces the value of a function pointer with a function that returns the provided values. It returns a function that restores the original function. If the function has multiple return values, pass them all.

Idiomatic usage will typically look like this:

func TestSomething(t *testing.T) {
	defer stub.StubFunc(&globalFunc, 42)()

	globalFunc() // returns 42
	// ...
}

If the test has subtests that use t.Parallel, use t.Cleanup instead of defer:

func TestSomething(t *testing.T) {
	t.Cleanup(stub.StubFunc(&globalFunc, 42))

	t.Run("subtest", func(t *testing.T) {
		t.Parallel()

		globalFunc() // returns 42
		// ...
	})
}

func Value

func Value[T any](ptr *T, value T) (restore func())

Value replaces the value of a pointer with a new value, and returns a function that restores the original value.

Idiomatic usage will typically look like this:

func TestSomething(t *testing.T) {
	defer stub.Value(&globalVar, newValue)()

	// ...
}

If the test has subtests that use t.Parallel, use t.Cleanup instead of defer:

func TestSomething(t *testing.T) {
	t.Cleanup(stub.Value(&globalVar, newValue))

	t.Run("subtest", func(t *testing.T) {
		t.Parallel()

		// ...
	})
}