// +build ignore,OMIT package string_test import ( "fmt" "strings" "testing" ) func TestIndex(t *testing.T) { var tests = []struct { s string sep string out int }{ {"", "", 0}, {"", "a", -1}, {"fo", "foo", -1}, {"foo", "foo", 0}, {"oofofoofooo", "f", 2}, // etc } for _, test := range tests { actual := strings.Index(test.s, test.sep) if actual != test.out { t.Errorf("Index(%q,%q) = %v; want %v", test.s, test.sep, actual, test.out) } } } func BenchmarkIndex(b *testing.B) { const s = "some_text=some☺value" for i := 0; i < b.N; i++ { strings.Index(s, "v") } } func ExampleIndex() { fmt.Println(strings.Index("chicken", "ken")) fmt.Println(strings.Index("chicken", "dmr")) // Output: // 4 // -1 }