IndexedDB: Fix prefetching; cache was always being bypassed.

content/common/indexed_db/proxy_webidbcursor_impl_unittest.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/common/indexed_db/proxy_webidbcursor_impl.h"
+
+#include "base/compiler_specific.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+class RendererWebIDBCursorImplTest : public testing::Test {
+};
+
+class MockIDBCallbacks : public WebKit::WebIDBCallbacks {
+public:
+  MockIDBCallbacks() : m_called(false) { }
+  void reset() { m_called = false; }
+  bool wasCalled() { return m_called; }
+  virtual void onSuccessWithContinuation() OVERRIDE { m_called = true; };
+ private:
+  bool m_called;
+};
+
+TEST_F(RendererWebIDBCursorImplTest, PrefetchTest) {
+  RendererWebIDBCursorImpl cursor(kInvalidIDBCursorId);

[michaeln, 2012/03/13 18:39:48]

I was wondering how the kInvalidIDBCursorId value was used since the impl never
sets it's cursor_id_ field to that value. looks like its used so the impl avoids
calling the 'dispatcher' when conducting the PrefetchTest.

Hmmm... feels dirty to modify the impl class in this way. I think the class was
just not designed with unittests in mind. The dependency on the 'dispatcher'
makes it difficult to compose them. Not sure you should add this test in this
way at this time? I'd be ok with the fix w/o a test.

If RendererWebIDBCursor utilized an interface to perform the methods asked of
the 'dispatcher', that interface could be mocked out for unittests which focus
on the core logic of that class (which looks likes is pretty much the prefetch
stuff), and unittests could also verify that the core logic calls out via the
'dispatcher' as it should. All that sounds like a battle for another day to me
though.

+
+  MockIDBCallbacks callbacks;
+
+  std::vector<IndexedDBKey> keys;
+  std::vector<IndexedDBKey> primary_keys;
+  std::vector<content::SerializedScriptValue> values;
+  for (int i = 0; i < 3; ++i) {
+    IndexedDBKey key;
+    IndexedDBKey primary_key;
+    content::SerializedScriptValue value;
+    key.SetNumber(i);
+    primary_key.SetNumber(i);
+    keys.push_back(key);
+    primary_keys.push_back(primary_key);
+    values.push_back(value);
+  }
+
+  cursor.SetPrefetchData(keys, primary_keys, values);
+
+  for (int i = 0; i < 3; ++i) {
+    callbacks.reset();
+    WebKit::WebIDBKey continueKey = WebKit::WebIDBKey::createNull();
+    WebKit::WebExceptionCode ec;
+    cursor.continueFunction(continueKey, &callbacks, ec);
+    EXPECT_TRUE(callbacks.wasCalled());
+    EXPECT_EQ(cursor.key().type(), WebKit::WebIDBKey::NumberType);
+    EXPECT_EQ(cursor.key().number(), i);
+  }
+}
+