Add a simple fuzzer that decodes (non incrementally) a bitstream. (#1630)

Uses the avif files in libavif/tests/data as seeds.

tests/CMakeLists.txt

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 48628e3..1916763 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -195,6 +195,7 @@
         )
     endif()
 
+    add_avif_fuzztest(avif_fuzztest_dec)
     add_avif_fuzztest(avif_fuzztest_dec_incr avifincrtest_helpers)
     add_avif_fuzztest(avif_fuzztest_enc_dec)
     add_avif_fuzztest(avif_fuzztest_read_image)

tests/gtest/avif_fuzztest_dec.cc

diff --git a/tests/gtest/avif_fuzztest_dec.cc b/tests/gtest/avif_fuzztest_dec.cc
new file mode 100644
index 0000000..a156f25
--- /dev/null
+++ b/tests/gtest/avif_fuzztest_dec.cc
@@ -0,0 +1,50 @@
+// Copyright 2023 Google LLC
+// SPDX-License-Identifier: BSD-2-Clause
+// Decodes an arbitrary sequence of bytes.
+
+#include <cstdint>
+
+#include "avif/avif.h"
+#include "avif_fuzztest_helpers.h"
+#include "fuzztest/fuzztest.h"
+#include "gtest/gtest.h"
+
+using ::fuzztest::Arbitrary;
+
+namespace libavif {
+namespace testutil {
+namespace {
+
+::testing::Environment* const stack_limit_env =
+    ::testing::AddGlobalTestEnvironment(
+        new FuzztestStackLimitEnvironment("524288"));  // 512 * 1024
+
+//------------------------------------------------------------------------------
+
+void Decode(const std::string& arbitrary_bytes, AvifDecoderPtr decoder) {
+  testutil::AvifImagePtr decoded(avifImageCreateEmpty(), avifImageDestroy);
+  ASSERT_NE(decoded, nullptr);
+  const avifResult result = avifDecoderReadMemory(
+      decoder.get(), decoded.get(),
+      reinterpret_cast<const uint8_t*>(arbitrary_bytes.data()),
+      arbitrary_bytes.size());
+  if (result == AVIF_RESULT_OK) {
+    EXPECT_GT(decoded->width, 0u);
+    EXPECT_GT(decoded->height, 0u);
+  }
+}
+
+constexpr uint32_t kMaxFileSize = 1024 * 1024;  // 1MB.
+
+FUZZ_TEST(DecodeAvifTest, Decode)
+    .WithDomains(Arbitrary<std::string>()
+                     .WithMaxSize(kMaxFileSize)
+                     .WithSeeds(GetTestImagesContents(
+                         kMaxFileSize, {AVIF_APP_FILE_FORMAT_AVIF})),
+                 ArbitraryAvifDecoder({AVIF_CODEC_CHOICE_AUTO}));
+
+//------------------------------------------------------------------------------
+
+}  // namespace
+}  // namespace testutil
+}  // namespace libavif