package mergo import ( "testing" ) type Student struct { Name string Books []string } var testData = []struct { S1 Student S2 Student ExpectedSlice []string }{ {Student{"Jack", []string{"a", "B"}}, Student{"Tom", []string{"1"}}, []string{"a", "B"}}, {Student{"Jack", []string{"a", "B"}}, Student{"Tom", []string{}}, []string{"a", "B"}}, {Student{"Jack", []string{}}, Student{"Tom", []string{"1"}}, []string{"1"}}, {Student{"Jack", []string{}}, Student{"Tom", []string{}}, []string{}}, } func TestIssue64MergeSliceWithOverride(t *testing.T) { for _, data := range testData { err := Merge(&data.S2, data.S1, WithOverride) if err != nil { t.Errorf("Error while merging %s", err) } if len(data.S2.Books) != len(data.ExpectedSlice) { t.Fatalf("Got %d elements in slice, but expected %d", len(data.S2.Books), len(data.ExpectedSlice)) } for i, val := range data.S2.Books { if val != data.ExpectedSlice[i] { t.Fatalf("Expected %s, but got %s while merging slice with override", data.ExpectedSlice[i], val) } } } }