Dump the uncompressed data's SHA1 to debug flaky tests

Dump the SHA1 of the uncompressed data in applypatch to confirm if we
are at least doing the bspatch part correctly. (I expect so since the actual
length of the uncompressed data matches the expected length).

Also try to decompress the deflate chunk inside the recovery image for
these two flacky tests. In theory, there shouldn't be randomness in
zlib; so we would know if we process the data wrongly if the deflate fails
to decompress.

Bug: 67849209
Test: recovery_component_test
Change-Id: Id947522153b1eeb0d10d161298a96fb045f92018
diff --git a/tests/component/applypatch_test.cpp b/tests/component/applypatch_test.cpp
index 292d76e..04055b9 100644
--- a/tests/component/applypatch_test.cpp
+++ b/tests/component/applypatch_test.cpp
@@ -37,6 +37,7 @@
 #include <android-base/unique_fd.h>
 #include <bsdiff/bsdiff.h>
 #include <openssl/sha.h>
+#include <zlib.h>
 
 #include "applypatch/applypatch.h"
 #include "applypatch/applypatch_modes.h"
@@ -46,6 +47,47 @@
 
 using namespace std::string_literals;
 
+// TODO(b/67849209) Remove after debug the flakiness.
+static void DecompressAndDumpRecoveryImage(const std::string& image_path) {
+  // Expected recovery_image structure
+  // chunk normal:  45066 bytes
+  // chunk deflate: 479442 bytes
+  // chunk normal:  5199 bytes
+  std::string recovery_content;
+  ASSERT_TRUE(android::base::ReadFileToString(image_path, &recovery_content));
+  ASSERT_GT(recovery_content.size(), 45066 + 5199);
+
+  z_stream strm = {};
+  strm.avail_in = recovery_content.size() - 45066 - 5199;
+  strm.next_in =
+      const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(recovery_content.data())) + 45066;
+
+  ASSERT_EQ(Z_OK, inflateInit2(&strm, -15));
+
+  constexpr unsigned int BUFFER_SIZE = 32768;
+  std::vector<uint8_t> uncompressed_data(BUFFER_SIZE);
+  size_t uncompressed_length = 0;
+  SHA_CTX ctx;
+  SHA1_Init(&ctx);
+  int ret;
+  do {
+    strm.avail_out = BUFFER_SIZE;
+    strm.next_out = uncompressed_data.data();
+
+    ret = inflate(&strm, Z_NO_FLUSH);
+    ASSERT_GE(ret, 0);
+
+    SHA1_Update(&ctx, uncompressed_data.data(), BUFFER_SIZE - strm.avail_out);
+    uncompressed_length += BUFFER_SIZE - strm.avail_out;
+  } while (ret != Z_STREAM_END);
+  inflateEnd(&strm);
+
+  uint8_t digest[SHA_DIGEST_LENGTH];
+  SHA1_Final(digest, &ctx);
+  GTEST_LOG_(INFO) << "uncompressed length " << uncompressed_length
+                   << " sha1: " << short_sha1(digest);
+}
+
 static void sha1sum(const std::string& fname, std::string* sha1, size_t* fsize = nullptr) {
   ASSERT_TRUE(sha1 != nullptr);
 
@@ -317,7 +359,11 @@
                                     recovery_img_sha1.c_str(),
                                     recovery_img_size_arg.c_str(),
                                     patch_arg.c_str() };
-  ASSERT_EQ(0, applypatch_modes(args.size(), args.data()));
+
+  if (applypatch_modes(args.size(), args.data()) != 0) {
+    DecompressAndDumpRecoveryImage(tgt_file.path);
+    FAIL();
+  }
 }
 
 TEST_F(ApplyPatchModesTest, PatchModeEmmcTargetWithMultiplePatches) {
@@ -360,7 +406,11 @@
   for (const auto& arg : args) {
     printf("  %s\n", arg);
   }
-  ASSERT_EQ(0, applypatch_modes(args.size(), args.data()));
+
+  if (applypatch_modes(args.size(), args.data()) != 0) {
+    DecompressAndDumpRecoveryImage(tgt_file.path);
+    FAIL();
+  }
 }
 
 // Ensures that applypatch works with a bsdiff based recovery-from-boot.p.