Add Base64 tests and fix a couple of bugs found.

Change-Id: I9762fe018be78cf38aa506026e78139e2479cd98

test/unit/test_Base64.cpp

@@ -0,0 +1,62 @@
+#include "Base64.h"
+
+#include "gtest/gtest.h"
+
+namespace ntimpl {
+
+struct Base64TestParam {
+  int plain_len;
+  const char* plain;
+  const char* encoded;
+};
+
+class Base64Test : public ::testing::TestWithParam<Base64TestParam> {
+ protected:
+  llvm::StringRef GetPlain() {
+    if (GetParam().plain_len < 0)
+      return llvm::StringRef(GetParam().plain);
+    else
+      return llvm::StringRef(GetParam().plain, GetParam().plain_len);
+  }
+};
+
+TEST_P(Base64Test, Encode) {
+  std::string s;
+  Base64Encode(GetPlain(), &s);
+  ASSERT_EQ(GetParam().encoded, s);
+}
+
+TEST_P(Base64Test, Decode) {
+  std::string s;
+  Base64Decode(GetParam().encoded, &s);
+  ASSERT_EQ(GetPlain(), s);
+}
+
+static Base64TestParam sample[] = {
+    {-1, "Send reinforcements", "U2VuZCByZWluZm9yY2VtZW50cw=="},
+    {-1, "Now is the time for all good coders\n to learn C++",
+     "Tm93IGlzIHRoZSB0aW1lIGZvciBhbGwgZ29vZCBjb2RlcnMKIHRvIGxlYXJuIEMrKw=="},
+    {-1,
+     "This is line one\nThis is line two\nThis is line three\nAnd so on...\n",
+     "VGhpcyBpcyBsaW5lIG9uZQpUaGlzIGlzIGxpbmUgdHdvClRoaXMgaXMgbGluZSB0aHJlZQpBb"
+     "mQgc28gb24uLi4K"},
+};
+
+INSTANTIATE_TEST_CASE_P(Base64Sample, Base64Test,
+                        ::testing::ValuesIn(sample));
+
+static Base64TestParam standard[] = {
+    {0, "", ""},
+    {1, "\0", "AA=="},
+    {2, "\0\0", "AAA="},
+    {3, "\0\0\0", "AAAA"},
+    {1, "\377", "/w=="},
+    {2, "\377\377", "//8="},
+    {3, "\377\377\377", "////"},
+    {2, "\xff\xef", "/+8="},
+};
+
+INSTANTIATE_TEST_CASE_P(Base64Standard, Base64Test,
+                        ::testing::ValuesIn(standard));
+ 
+}  // namespace ntimpl