Disk cache: Clarify API contract and delete spurious delay.

net/disk_cache/backend_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 "base/basictypes.h"
 #include "base/file_util.h"
 #include "base/metrics/field_trial.h"
 #include "base/port.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
@@ skipping 1586 matching lines @@
   Time middle_start = Time::Now();
 
   ASSERT_EQ(net::OK, CreateEntry("second", &entry));
   entry->Close();
   ASSERT_EQ(net::OK, CreateEntry("third", &entry));
   entry->Close();
   FlushQueueForTest();
 
   AddDelay();
   Time middle_end = Time::Now();
-  AddDelay();

[gavinp, 2014/03/21 11:20:39]

This delay is not spurious; for caches that use coarse timing (second resolution
for instance in simple cache), this delay keeps the first doom from erasing
entries created after time middle_end.

[rvargas (doing something else), 2014/03/21 18:14:41]

Could you expand on that?

The test as it is _without_ this delay is meant to make sure that the cache
doesn't delete entries created _after_ |middle_end|, as that is the only thing
visible by the caller. Failing the test without the delay still sounds like a
bug to me as the backend is not respecting the provided end time.

 
   ASSERT_EQ(net::OK, CreateEntry("fourth", &entry));
   entry->Close();
   ASSERT_EQ(net::OK, OpenEntry("fourth", &entry));
   entry->Close();
   FlushQueueForTest();
 
   AddDelay();
   Time final = Time::Now();
 
@@ skipping 1605 matching lines @@
   SetSimpleCacheMode();
   SetMaxSize(0x100000);
   BackendLoad();
 }
 
 TEST_F(DiskCacheBackendTest, SimpleDoomRecent) {
   SetSimpleCacheMode();
   BackendDoomRecent();
 }
 
-TEST_F(DiskCacheBackendTest, SimpleDoomBetween) {
+// crbug.com/330926
+TEST_F(DiskCacheBackendTest, DISABLED_SimpleDoomBetween) {
   SetSimpleCacheMode();
   BackendDoomBetween();
 }
 
 TEST_F(DiskCacheBackendTest, SimpleCacheDoomAll) {
   SetSimpleCacheMode();
   BackendDoomAll();
 }
 
 TEST_F(DiskCacheBackendTest, SimpleCacheAppCacheOnlyDoomAll) {
@@ skipping 244 matching lines @@
   void* iter = NULL;
   size_t count = 0;
   ASSERT_TRUE(EnumerateAndMatchKeys(-1, &iter, &keys_to_match, &count));
   cache_->EndEnumeration(&iter);
 
   EXPECT_EQ(key_pool.size(), count);
   EXPECT_TRUE(keys_to_match.empty());
 }
 
 #endif  // defined(OS_POSIX)