package lib import ( "reflect" "testing" "time" "github.com/stretchr/testify/require" ) func makeFullTelemetryConfig(t *testing.T) TelemetryConfig { var ( strSliceVal = []string{"foo"} strVal = "foo" intVal = int64(1 * time.Second) ) cfg := TelemetryConfig{} cfgP := reflect.ValueOf(&cfg) cfgV := cfgP.Elem() for i := 0; i < cfgV.NumField(); i++ { f := cfgV.Field(i) if !f.IsValid() || !f.CanSet() { continue } // Set non-zero values for all fields. We only implement kinds that exist // now for brevity but will fail the test if a new field type is added since // this is likely not implemented in MergeDefaults either. switch f.Kind() { case reflect.Slice: if f.Type() != reflect.TypeOf(strSliceVal) { t.Fatalf("unknown slice type in TelemetryConfig." + " You need to update MergeDefaults and this test code.") } f.Set(reflect.ValueOf(strSliceVal)) case reflect.Int, reflect.Int64: // time.Duration == int64 f.SetInt(intVal) case reflect.String: f.SetString(strVal) case reflect.Bool: f.SetBool(true) default: t.Fatalf("unknown field type in TelemetryConfig" + " You need to update MergeDefaults and this test code.") } } return cfg } func TestTelemetryConfig_MergeDefaults(t *testing.T) { tests := []struct { name string cfg TelemetryConfig defaults TelemetryConfig want TelemetryConfig }{ { name: "basic merge", cfg: TelemetryConfig{ StatsiteAddr: "stats.it:4321", }, defaults: TelemetryConfig{ StatsdAddr: "localhost:5678", StatsiteAddr: "localhost:1234", }, want: TelemetryConfig{ StatsdAddr: "localhost:5678", StatsiteAddr: "stats.it:4321", }, }, { // This test uses reflect to build a TelemetryConfig with every value set // to ensure that we exercise every possible field type. This means that // if new fields are added that are not supported types in the code, this // test should either ensure they work or fail to build the test case and // fail the test. name: "exhaustive", cfg: TelemetryConfig{}, defaults: makeFullTelemetryConfig(t), want: makeFullTelemetryConfig(t), }, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { c := tt.cfg c.MergeDefaults(&tt.defaults) require.Equal(t, tt.want, c) }) } }