Add 'names.IsOptInRegion'.

names/names.go

@@ -185,6 +185,23 @@ func DNSSuffixForPartition(partition string) string {
 	}
 }
 
+func IsOptInRegion(region string) bool {
+	switch region {
+	case AFSouth1RegionID,
+		APEast1RegionID, APSouth2RegionID,
+		APSoutheast3RegionID, APSoutheast4RegionID,
+		CAWest1RegionID,
+		EUCentral2RegionID,
+		EUSouth1RegionID, EUSouth2RegionID,
+		ILCentral1RegionID,
+		MECentral1RegionID,
+		MESouth1RegionID:
+		return true
+	default:
+		return false
+	}
+}
+
 func PartitionForRegion(region string) string {
 	switch region {
 	case "":

names/names_test.go

@@ -58,6 +58,53 @@ func TestDNSSuffixForPartition(t *testing.T) {
 	}
 }
 
+func TestIsOptInRegion(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name     string
+		input    string
+		expected bool
+	}{
+		{
+			name:     "empty",
+			input:    "",
+			expected: false,
+		},
+		{
+			name:     "China",
+			input:    CNNorth1RegionID,
+			expected: false,
+		},
+		{
+			name:     "GovCloud",
+			input:    USGovWest1RegionID,
+			expected: false,
+		},
+		{
+			name:     "standard opt-in",
+			input:    CAWest1RegionID,
+			expected: true,
+		},
+		{
+			name:     "standard not opt-in",
+			input:    CACentral1RegionID,
+			expected: false,
+		},
+	}
+
+	for _, testCase := range testCases {
+		testCase := testCase
+		t.Run(testCase.name, func(t *testing.T) {
+			t.Parallel()
+
+			if got, want := IsOptInRegion(testCase.input), testCase.expected; got != want {
+				t.Errorf("got: %t, expected: %t", got, want)
+			}
+		})
+	}
+}
+
 func TestPartitionForRegion(t *testing.T) {
 	t.Parallel()