SimpleCache: Add a test that covers recovery from missing index.

net/disk_cache/backend_unittest.cc

Index: net/disk_cache/backend_unittest.cc
diff --git a/net/disk_cache/backend_unittest.cc b/net/disk_cache/backend_unittest.cc
index ca0e0ee8754e18804dd8b13695208b6bfa747f90..79fcdf728352016fa0e23bd7539f47ba9fba7ecc 100644
--- a/net/disk_cache/backend_unittest.cc
+++ b/net/disk_cache/backend_unittest.cc
@@ -3886,6 +3886,41 @@ TEST_F(DiskCacheBackendTest, SimpleCacheEnumerationBasics) {
   EXPECT_TRUE(keys_to_match.empty());
 }
 
+TEST_F(DiskCacheBackendTest, SimpleCacheIndexRecovery) {
+  // Make sure we can recover set of entries when the index was removed.
+  SetSimpleCacheMode();
+  InitCache();
+  std::set<std::string> key_pool;
+  ASSERT_TRUE(CreateSetOfRandomEntries(&key_pool));
+
+  cache_.reset();
+
+  // Give it a chance to write out the index, so we can delete it (rather
+  // than have it write it after we delete it).
+  disk_cache::SimpleBackendImpl::FlushWorkerPoolForTesting();
+  base::RunLoop().RunUntilIdle();
+
+  base::FilePath index_path =
+      cache_path_.AppendASCII("index-dir").AppendASCII("the-real-index");
+  ASSERT_TRUE(base::DeleteFile(index_path, false));
+
+  DisableFirstCleanup();
+  InitCache();
+  // A bit surprising, but it calls it "NEWCACHE" if there was no index,
+  // even if it reconstructed non-zero things.
+  EXPECT_EQ(disk_cache::SimpleIndex::INITIALIZE_METHOD_NEWCACHE,
+            simple_cache_impl_->index()->init_method());
+
+  // Check that enumeration returns all entries.
+  std::set<std::string> keys_to_match(key_pool);
+  std::unique_ptr<TestIterator> iter = CreateIterator();
+  size_t count = 0;
+  ASSERT_TRUE(EnumerateAndMatchKeys(-1, iter.get(), &keys_to_match, &count));
+  iter.reset();
+  EXPECT_EQ(key_pool.size(), count);
+  EXPECT_TRUE(keys_to_match.empty());
+}
+
 // Tests that the enumerations are not affected by dooming an entry in the
 // middle.
 TEST_F(DiskCacheBackendTest, SimpleCacheEnumerationWhileDoomed) {