AssertAssociationCount(t, user, "Pets", 5, "AfterAppendSlice")

	// Replace
	pet2 := Pet{Name: "pet-has-many-replace"}

	if err := DB.Model(&user2).Association("Pets").Replace(&pet2); err != nil {
		t.Fatalf("Error happened when append pet, got %v", err)
	}

	if pet2.ID == 0 {
		t.Fatalf("pet2's ID should be created")
	}

	user.Pets = []*Pet{&pet2}
	CheckUser(t, user2, user)

	output := runTestProg(t, "testprog", "PanicTraceback")
	want := "panic: hello\n\tpanic: panic pt2\n\tpanic: panic pt1\n"
	if !strings.HasPrefix(output, want) {
		t.Fatalf("output does not start with %q:\n%s", want, output)
	}

	// Check functions in the traceback.
	fns := []string{"main.pt1.func1", "panic", "main.pt2.func1", "panic", "main.pt2", "main.pt1"}
	for _, fn := range fns {