1 files changed, 102 insertions, 0 deletions
diff --git a/src/crypto/x509/parser_test.go b/src/crypto/x509/parser_test.go
new file mode 100644
index 0000000000..d7cf7ea758
--- /dev/null
+++ b/src/crypto/x509/parser_test.go
@@ -0,0 +1,102 @@
+// Copyright 2021 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 x509
+
+import (
+	"encoding/asn1"
+	"testing"
+
+	cryptobyte_asn1 "golang.org/x/crypto/cryptobyte/asn1"
+)
+
+func TestParseASN1String(t *testing.T) {
+	tests := []struct {
+		name        string
+		tag         cryptobyte_asn1.Tag
+		value       []byte
+		expected    string
+		expectedErr string
+	}{
+		{
+			name:     "T61String",
+			tag:      cryptobyte_asn1.T61String,
+			value:    []byte{80, 81, 82},
+			expected: string("PQR"),
+		},
+		{
+			name:     "PrintableString",
+			tag:      cryptobyte_asn1.PrintableString,
+			value:    []byte{80, 81, 82},
+			expected: string("PQR"),
+		},
+		{
+			name:        "PrintableString (invalid)",
+			tag:         cryptobyte_asn1.PrintableString,
+			value:       []byte{1, 2, 3},
+			expectedErr: "invalid PrintableString",
+		},
+		{
+			name:     "UTF8String",
+			tag:      cryptobyte_asn1.UTF8String,
+			value:    []byte{80, 81, 82},
+			expected: string("PQR"),
+		},
+		{
+			name:        "UTF8String (invalid)",
+			tag:         cryptobyte_asn1.UTF8String,
+			value:       []byte{255},
+			expectedErr: "invalid UTF-8 string",
+		},
+		{
+			name:     "BMPString",
+			tag:      cryptobyte_asn1.Tag(asn1.TagBMPString),
+			value:    []byte{80, 81},
+			expected: string("偑"),
+		},
+		{
+			name:        "BMPString (invalid length)",
+			tag:         cryptobyte_asn1.Tag(asn1.TagBMPString),
+			value:       []byte{255},
+			expectedErr: "invalid BMPString",
+		},
+		{
+			name:     "IA5String",
+			tag:      cryptobyte_asn1.IA5String,
+			value:    []byte{80, 81},
+			expected: string("PQ"),
+		},
+		{
+			name:        "IA5String (invalid)",
+			tag:         cryptobyte_asn1.IA5String,
+			value:       []byte{255},
+			expectedErr: "invalid IA5String",
+		},
+		{
+			name:     "NumericString",
+			tag:      cryptobyte_asn1.Tag(asn1.TagNumericString),
+			value:    []byte{49, 50},
+			expected: string("12"),
+		},
+		{
+			name:        "NumericString (invalid)",
+			tag:         cryptobyte_asn1.Tag(asn1.TagNumericString),
+			value:       []byte{80},
+			expectedErr: "invalid NumericString",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			out, err := parseASN1String(tc.tag, tc.value)
+			if err != nil && err.Error() != tc.expectedErr {
+				t.Fatalf("parseASN1String returned unexpected error: got %q, want %q", err, tc.expectedErr)
+			} else if err == nil && tc.expectedErr != "" {
+				t.Fatalf("parseASN1String didn't fail, expected: %s", tc.expectedErr)
+			}
+			if out != tc.expected {
+				t.Fatalf("parseASN1String returned unexpected value: got %q, want %q", out, tc.expected)
+			}
+		})
+	}
+}