Go generic test must utility

must.go

package testx

import "testing"

func Must0(t *testing.T) func(error) {
	return func(err error) {
		t.Helper()
		if err != nil {
			t.Fatal(err)
		}
	}
}

func Must1[T any](t *testing.T) func(T, error) T {
	return func(ret1 T, err error) T {
		t.Helper()
		if err != nil {
			t.Fatal(err)
		}
		return ret1
	}
}

func Must2[T1 any, T2 any](t *testing.T) func(T1, T2, error) (T1, T2) {
	return func(ret1 T1, ret2 T2, err error) (T1, T2) {
		t.Helper()
		if err != nil {
			t.Fatal(err)
		}
		return ret1, ret2
	}
}

must_test.go

package testx

import (
	"errors"
	"testing"
)

func TestMust0(t *testing.T) {
	f := func(ok bool) error {
		if ok {
			return nil
		}
		return errors.New("error")
	}

	Must0(t)(f(true))
	Must0(t)(f(false))
}

func TestMust1(t *testing.T) {
	f := func(ok bool) (int, error) {
		if ok {
			return 1, nil
		}
		return 0, errors.New("error")
	}

	v := Must1[int](t)(f(true))
	if got, want := v, 1; got != want {
		t.Errorf("result mismatch, got=%v, want=%v", got, want)
	}
	Must1[int](t)(f(false))
}

func TestMust2(t *testing.T) {
	f := func(ok bool) (int, string, error) {
		if ok {
			return 1, "foo", nil
		}
		return 0, "", errors.New("error")
	}

	v, s := Must2[int, string](t)(f(true))
	if got, want := v, 1; got != want {
		t.Errorf("result1 mismatch, got=%v, want=%v", got, want)
	}
	if got, want := s, "foo"; got != want {
		t.Errorf("result2 mismatch, got=%v, want=%v", got, want)
	}
	Must2[int, string](t)(f(false))
}

$ go test -v
=== RUN   TestMust0
    must_test.go:17: error
--- FAIL: TestMust0 (0.00s)
=== RUN   TestMust1
    must_test.go:32: error
--- FAIL: TestMust1 (0.00s)
=== RUN   TestMust2
    must_test.go:50: error
--- FAIL: TestMust2 (0.00s)
FAIL
exit status 1

Run it on the Go Playground: https://go.dev/play/p/uFEE6pJ7w42