MHTMLTest::TestMHTMLEncoding checks generated MTHML is well formed.

third_party/WebKit/Source/web/tests/MHTMLTest.cpp

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/dom/Document.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Location.h"
 #include "core/page/Page.h"
 #include "platform/SerializedResource.h"
 #include "platform/SharedBuffer.h"
 #include "platform/mhtml/MHTMLArchive.h"
+#include "platform/mhtml/MHTMLParser.h"
 #include "platform/testing/URLTestHelpers.h"
 #include "platform/testing/UnitTestHelpers.h"
 #include "platform/weborigin/KURL.h"
 #include "platform/weborigin/SchemeRegistry.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebString.h"
 #include "public/platform/WebURL.h"
 #include "public/platform/WebURLLoaderMockFactory.h"
 #include "public/platform/WebURLRequest.h"
 #include "public/platform/WebURLResponse.h"
@@ skipping 152 matching lines @@
 
   SecurityOrigin* origin = document->GetSecurityOrigin();
   EXPECT_STRNE("localhost", origin->Domain().Ascii().data());
 }
 
 TEST_F(MHTMLTest, TestMHTMLEncoding) {
   AddTestResources();
   RefPtr<RawData> data = Serialize("Test Serialization", "text/html",
                                    MHTMLArchive::kUseDefaultEncoding);
 
+  // Validate the generated MHTML.
+  MHTMLParser parser(SharedBuffer::Create(data->data(), data->length()));
+  ASSERT_FALSE(parser.ParseArchive().IsEmpty()) << "Invalid MHTML";

[Łukasz Anforowicz, 2017/04/25 19:01:24]

Would it be possible to increase the coverage of the new check by moving the
check to MHTMLTest::GenerateMHTMLData?  If some callers of
MHTMLTest::GenerateMHTMLData expect creation of malformed MHTML, then maybe we
can add a parameter to MHTMLTest::GenerateMHTMLData (or a field to MHTMLTest?)
that tells the code whether the asserts above are appropriate.

[carlosk, 2017/04/25 19:49:30]

Done.

+
   // Read the MHTML data line per line and do some pseudo-parsing to make sure
   // the right encoding is used for the different sections.
   LineReader line_reader(std::string(data->data(), data->length()));
   int section_checked_count = 0;
   const char* expected_encoding = 0;
   std::string line;
   while (line_reader.GetNextLine(&line)) {
     if (line.compare(0, 13, "Content-Type:") == 0) {
       ASSERT_FALSE(expected_encoding);
       if (line.find("multipart/related;") != std::string::npos) {
@@ skipping 59 matching lines @@
   // Full sandboxing should be turned on.
   EXPECT_TRUE(document->IsSandboxed(kSandboxAll));
 
   // MHTML document should be loaded into unique origin.
   EXPECT_TRUE(document->GetSecurityOrigin()->IsUnique());
   // Script execution should be disabled.
   EXPECT_FALSE(document->CanExecuteScripts(kNotAboutToExecuteScript));
 }
 
 }  // namespace blink