Add a test for the HexDecode method.

core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp

Index: core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..f01e21293c62f81d12b04682cbc56e68335f04e0
--- /dev/null
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp
@@ -0,0 +1,52 @@
+// Copyright 2015 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+#include "../../../include/fpdfapi/fpdf_parser.h"
+
+TEST(fpdf_parser_decode, HexDecode) {
+  {
+    // Empty src string.
+    uint8_t* dest = nullptr;
+    FX_DWORD dest_size;
+    uint8_t src[] = "";
+    EXPECT_EQ(0, HexDecode(src, 0, dest, dest_size));
+    EXPECT_EQ(0, dest_size);
+    EXPECT_EQ('\0', dest[0]);
+  }
+
+  {
+    // Regular conversion.
+    uint8_t* dest = nullptr;
+    FX_DWORD dest_size;
+    uint8_t src[] = "12Ac>zzz";
+    EXPECT_EQ(5, HexDecode(src, 8, dest, dest_size));
+    EXPECT_EQ(2, dest_size);
+    EXPECT_EQ(18, dest[0]);
+    EXPECT_EQ(172, dest[1]);
+  }
+
+  {
+    // Non-multiple length.
+    uint8_t* dest = nullptr;
+    FX_DWORD dest_size;
+    uint8_t src[] = "12A>zzz";
+    EXPECT_EQ(4, HexDecode(src, 8, dest, dest_size));
+    EXPECT_EQ(2, dest_size);
+    EXPECT_EQ(18, dest[0]);
+    EXPECT_EQ(160, dest[1]);
+  }
+
+  {
+    // Skips unknown characters.
+    uint8_t* dest = nullptr;
+    FX_DWORD dest_size;
+    uint8_t src[] = "12tk  \tAc>zzz";
+    EXPECT_EQ(10, HexDecode(src, 13, dest, dest_size));
+    EXPECT_EQ(2, dest_size);
+    EXPECT_EQ(18, dest[0]);
+    EXPECT_EQ(172, dest[1]);
+  }
+}