Avoid dereferencing find() without checking for == end()

media/base/audio_video_metadata_extractor_unittest.cc

Index: media/base/audio_video_metadata_extractor_unittest.cc
diff --git a/media/base/audio_video_metadata_extractor_unittest.cc b/media/base/audio_video_metadata_extractor_unittest.cc
index d67808f16eb6a4b792ba531593c00edc7d2a8911..fe57c3f6dae46dbcb311f2157a89c6a4e0f4b8dc 100644
--- a/media/base/audio_video_metadata_extractor_unittest.cc
+++ b/media/base/audio_video_metadata_extractor_unittest.cc
@@ -61,6 +61,16 @@ TEST(AudioVideoMetadataExtractorTest, AudioOGG) {
   EXPECT_EQ(0u, extractor->attached_images_bytes().size());
 }
 
+const std::string GetTagValue(
+    const media::AudioVideoMetadataExtractor::TagDictionary& tags,
+    const char* tag_name) {
+  auto tag_data = tags.find(tag_name);
+  EXPECT_NE(tag_data, tags.end());

[DaleCurtis, 2016/01/28 21:54:47]

I'd just drop this since it's just noise in the test log if it fails here (vs on
the actual test line below) and use a ternary for style.

[brucedawson, 2016/01/28 22:17:26]

Sounds good.

The original advice was to use ASSERT, but that does a return; and therefore
cannot be used from a helper function such as this.

+  if (tag_data == tags.end())
+    return "";
+  return tag_data->second;
+}
+
 TEST(AudioVideoMetadataExtractorTest, AudioWAV) {
   scoped_ptr<AudioVideoMetadataExtractor> extractor =
       GetExtractor("sfx_u8.wav", true, true, 0, -1, -1);
@@ -72,9 +82,9 @@ TEST(AudioVideoMetadataExtractorTest, AudioWAV) {
 
   EXPECT_EQ(2u, extractor->stream_infos()[0].tags.size());
   EXPECT_EQ("Lavf54.37.100",
-            extractor->stream_infos()[0].tags.find("encoder")->second);
+            GetTagValue(extractor->stream_infos()[0].tags, "encoder"));
   EXPECT_EQ("Amadeus Pro",
-            extractor->stream_infos()[0].tags.find("encoded_by")->second);
+            GetTagValue(extractor->stream_infos()[0].tags, "encoded_by"));
 
   EXPECT_EQ("pcm_u8", extractor->stream_infos()[1].type);
   EXPECT_EQ(0u, extractor->stream_infos()[1].tags.size());