assert.go

@@ -156,6 +156,7 @@ func (a Assert) SameElements(expected, actual interface{}, msg ...interface{}) {
 	a.f(false, msg, ``)
 }
 
+// Cmp assert wrapper for go-cmp
 func (a Assert) Cmp(expected, actual interface{}, opts ...cmp.Option) {
 	a.t.Helper()
 	diff := cmp.Diff(expected, actual, opts...)
@@ -165,3 +166,11 @@ func (a Assert) Cmp(expected, actual interface{}, opts ...cmp.Option) {
 
 	a.f(false, nil, "\n"+diff)
 }
+
+// NCmp assert wrapper for go-cmp but fails when !Equal
+func (a Assert) NCmp(expected, actual interface{}, opts ...cmp.Option) {
+	a.t.Helper()
+
+	ok := cmp.Equal(expected, actual, opts...)
+	a.f(!ok, nil, `Should not be %#v, but it is`, expected)
+}

assert_test.go

@@ -177,3 +177,18 @@ func TestCmpTimezones(t *testing.T) {
 	fa.Cmp(&A{ti}, &A{ti2})
 	assert.True(ft.GotError())
 }
+
+func TestNCmp(t *testing.T) {
+	assert := New(t)
+	ft, fa := newFakeT()
+
+	type A struct {
+		S string
+	}
+
+	fa.NCmp(A{"not"}, A{"equal"})
+	assert.False(ft.GotError())
+
+	fa.NCmp(A{"equal"}, A{"equal"})
+	assert.True(ft.GotError())
+}