SkPDF/Tests: imporve test coverage.

tests/PDFDeflateWStreamTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDeflate.h"
 #include "SkRandom.h"
 #include "Test.h"
@@ skipping 83 matching lines @@
 
     inflateEnd(&flateData);
     if (rc != Z_STREAM_END) {
         ERRORF(reporter, "Zlib: inflateEnd failed");
         return nullptr;
     }
     return decompressedDynamicMemoryWStream.detachAsStream();
 }
 }  // namespace
 
-DEF_TEST(SkDeflateWStream, r) {
+DEF_TEST(SkPDF_DeflateWStream, r) {
     SkRandom random(123456);
     for (int i = 0; i < 50; ++i) {
         uint32_t size = random.nextULessThan(10000);
         SkAutoTMalloc<uint8_t> buffer(size);
         for (uint32_t j = 0; j < size; ++j) {
             buffer[j] = random.nextU() & 0xff;
         }
 
         SkDynamicMemoryWStream dynamicMemoryWStream;
         {
             SkDeflateWStream deflateWStream(&dynamicMemoryWStream);
             uint32_t j = 0;
             while (j < size) {
                 uint32_t writeSize =
                         SkTMin(size - j, random.nextRangeU(1, 400));
                 if (!deflateWStream.write(&buffer[j], writeSize)) {
                     ERRORF(r, "something went wrong.");
                     return;
                 }
                 j += writeSize;
             }
+            REPORTER_ASSERT(r, deflateWStream.bytesWritten() == size);
         }
         SkAutoTDelete<SkStreamAsset> compressed(
                 dynamicMemoryWStream.detachAsStream());
         SkAutoTDelete<SkStreamAsset> decompressed(stream_inflate(r, compressed));
 
         if (!decompressed) {
             ERRORF(r, "Decompression failed.");
             return;
         }
         if (decompressed->getLength() != size) {
@@ skipping 16 matching lines @@
         for (uint32_t i = 0; i < minLength; ++i) {
             uint8_t c;
             SkDEBUGCODE(size_t rb =)decompressed->read(&c, sizeof(uint8_t));
             SkASSERT(sizeof(uint8_t) == rb);
             if (buffer[i] != c) {
                 ERRORF(r, "Decompression failed at byte %u.", (unsigned)i);
                 break;
             }
         }
     }
+    SkDeflateWStream emptyDeflateWStream(nullptr);
+    REPORTER_ASSERT(r, !emptyDeflateWStream.writeText("FOO"));
 }