http: add tests for reading TLS private keys

This commit adds some test cases to verify that
private keys are read, decrypted and parsed
correctly.

Signed-off-by: Andreas Auernhammer <[email protected]>

internal/http/testdata/privatekeys/encrypted.pem

@@ -0,0 +1,8 @@
+-----BEGIN EC PRIVATE KEY-----
+Proc-Type: 4,ENCRYPTED
+DEK-Info: AES-256-CBC,E1CF19C5B05C92E1D8D88867779455F8
+
+hX5Pwa91m/+DGSsE4ON34/fsFyXOakpjnYK7IrbVWHagbMcDgDGTgwkeCqlEX7U/
+BQiX8oGFR/ff+R+TcLRI6tGfmns9B4QS3RVMeY965F1zHysMn/jjIgzQyfmo8YNI
+K/11h1SW8SEmbMzmCIhnagYmt/JQrjJVbgGlQgxHV0w=
+-----END EC PRIVATE KEY-----

internal/http/testdata/privatekeys/plaintext.pem

@@ -0,0 +1,5 @@
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIB4u/+f//HoqSAdVd9DN91JRhQoHLml+/gbvK91SYbK5oAoGCCqGSM49
+AwEHoUQDQgAEZwWOkBVrkeLKYE5QFwDzDDHwkBjiVFJ+BgXOaXHTkRcjclh7k85r
+wx4zTr/x27oWtlDusD/JTa8dSqJADEF3HA==
+-----END EC PRIVATE KEY-----

internal/http/tls_test.go

@@ -0,0 +1,33 @@
+// Copyright 2021 - MinIO, Inc. All rights reserved.
+// Use of this source code is governed by the AGPLv3
+// license that can be found in the LICENSE file.
+
+package http
+
+import (
+	"testing"
+)
+
+var readPrivateKeyTests = []struct {
+	FilePath   string
+	Password   string
+	ShouldFail bool
+}{
+	{FilePath: "testdata/privatekeys/plaintext.pem", Password: ""},                                     // 0
+	{FilePath: "testdata/privatekeys/plaintext.pem", Password: "ignored_password"},                     // 1
+	{FilePath: "testdata/privatekeys/encrypted.pem", Password: "correct_password"},                     // 2
+	{FilePath: "testdata/privatekeys/encrypted.pem", Password: "", ShouldFail: true},                   // 3
+	{FilePath: "testdata/privatekeys/encrypted.pem", Password: "incorrect_password", ShouldFail: true}, // 4
+}
+
+func TestReadPrivateKey(t *testing.T) {
+	for i, test := range readPrivateKeyTests {
+		_, err := readPrivateKey(test.FilePath, test.Password)
+		if err != nil && !test.ShouldFail {
+			t.Fatalf("Test %d: failed to read private key %q: %v", i, test.FilePath, err)
+		}
+		if err == nil && test.ShouldFail {
+			t.Fatalf("Test %d: reading private key %q should have failed", i, test.FilePath)
+		}
+	}
+}