1 files changed, 99 insertions, 0 deletions
diff --git a/src/time/tzdata_test.go b/src/time/tzdata_test.go
new file mode 100644
index 0000000..33c6589
--- /dev/null
+++ b/src/time/tzdata_test.go
@@ -0,0 +1,99 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package time_test
+
+import (
+	"reflect"
+	"testing"
+	"time"
+	_ "time/tzdata"
+)
+
+var zones = []string{
+	"Asia/Jerusalem",
+	"America/Los_Angeles",
+}
+
+func TestEmbeddedTZData(t *testing.T) {
+	undo := time.DisablePlatformSources()
+	defer undo()
+
+	for _, zone := range zones {
+		ref, err := time.LoadLocation(zone)
+		if err != nil {
+			t.Errorf("LoadLocation(%q): %v", zone, err)
+			continue
+		}
+
+		embedded, err := time.LoadFromEmbeddedTZData(zone)
+		if err != nil {
+			t.Errorf("LoadFromEmbeddedTZData(%q): %v", zone, err)
+			continue
+		}
+		sample, err := time.LoadLocationFromTZData(zone, []byte(embedded))
+		if err != nil {
+			t.Errorf("LoadLocationFromTZData failed for %q: %v", zone, err)
+			continue
+		}
+
+		// Compare the name and zone fields of ref and sample.
+		// The tx field changes faster as tzdata is updated.
+		// The cache fields are expected to differ.
+		v1 := reflect.ValueOf(ref).Elem()
+		v2 := reflect.ValueOf(sample).Elem()
+		typ := v1.Type()
+		nf := typ.NumField()
+		found := 0
+		for i := 0; i < nf; i++ {
+			ft := typ.Field(i)
+			if ft.Name != "name" && ft.Name != "zone" {
+				continue
+			}
+			found++
+			if !equal(t, v1.Field(i), v2.Field(i)) {
+				t.Errorf("zone %s: system and embedded tzdata field %s differs", zone, ft.Name)
+			}
+		}
+		if found != 2 {
+			t.Errorf("test must be updated for change to time.Location struct")
+		}
+	}
+}
+
+// equal is a small version of reflect.DeepEqual that we use to
+// compare the values of zoneinfo unexported fields.
+func equal(t *testing.T, f1, f2 reflect.Value) bool {
+	switch f1.Type().Kind() {
+	case reflect.Slice:
+		if f1.Len() != f2.Len() {
+			return false
+		}
+		for i := 0; i < f1.Len(); i++ {
+			if !equal(t, f1.Index(i), f2.Index(i)) {
+				return false
+			}
+		}
+		return true
+	case reflect.Struct:
+		nf := f1.Type().NumField()
+		for i := 0; i < nf; i++ {
+			if !equal(t, f1.Field(i), f2.Field(i)) {
+				return false
+			}
+		}
+		return true
+	case reflect.String:
+		return f1.String() == f2.String()
+	case reflect.Bool:
+		return f1.Bool() == f2.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return f1.Int() == f2.Int()
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return f1.Uint() == f2.Uint()
+	default:
+		t.Errorf("test internal error: unsupported kind %v", f1.Type().Kind())
+		return true
+	}
+}