Golang Testify go-cmp Partial Equal

example_test.go

package main

import (
	"fmt"
	"testing"
	"time"

	"github.com/google/go-cmp/cmp"
	"github.com/google/go-cmp/cmp/cmpopts"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

type B struct {
	Foo time.Time
	Bar time.Time
}

type A struct {
	B
	C int
}

func TestStructPartialEquality(t *testing.T) {
	a1 := A{B: B{Foo: time.Unix(1, 0)}, C: 3}
	a2 := a1
	a2.Foo = time.Unix(2, 0)
	a2.Bar = time.Now() // comment to PASS, uncomment to FAIL
	diffOpts := cmpopts.IgnoreFields(a2, "B.Foo")
	PartialEqual(t, a1, a2, diffOpts)

	//require.True(t, cmp.Equal(a1, a2, diffOpts), cmp.Diff(a1, a2, diffOpts))

	// diff := cmp.Diff(a1, a2, cmpopts.IgnoreFields(A{}, "B.Foo"))
	//
	//	if diff != "" {
	//		t.Errorf("THE DIFF %+v", diff)
	//	}
}

// PartialEqual asserts that two objects are equal, depending on what equal means
//
// For instance, you may pass options to ignore certain fields
func PartialEqual(t require.TestingT, expected, actual any, diffOpts cmp.Option, msgAndArgs ...any) {
	if h, ok := t.(tHelper); ok {
		h.Helper()
	}

	if cmp.Equal(expected, actual, diffOpts) {
		return
	}

	diff := cmp.Diff(expected, actual, diffOpts)
	assert.Fail(t, fmt.Sprintf("Not equal: \n"+
		"expected: %s\n"+
		"actual  : %s%s", expected, actual, diff), msgAndArgs...)
	return
}

type tHelper interface {
	Helper()
}