[iOS] Upstream some stability code

ios/chrome/browser/metrics/previous_session_info_unittest.mm

Index: ios/chrome/browser/metrics/previous_session_info_unittest.mm
diff --git a/ios/chrome/browser/metrics/previous_session_info_unittest.mm b/ios/chrome/browser/metrics/previous_session_info_unittest.mm
new file mode 100644
index 0000000000000000000000000000000000000000..1ab97c8931f5640408e059d3ac497da3cf2da935
--- /dev/null
+++ b/ios/chrome/browser/metrics/previous_session_info_unittest.mm
@@ -0,0 +1,189 @@
+// Copyright 2015 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 "ios/chrome/browser/metrics/previous_session_info.h"
+
+#include "base/strings/sys_string_conversions.h"
+#include "ios/public/provider/chrome/browser/chrome_browser_provider.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/gtest_mac.h"
+
+namespace {
+
+// Key in the UserDefaults for a boolean value keeping track of memory warnings.
+NSString* const kDidSeeMemoryWarningShortlyBeforeTerminating =
+    @"DidSeeMemoryWarning";
+
+// Key in the NSUserDefaults for a string value that stores the version of the
+// last session.
+NSString* const kLastRanVersion = @"LastRanVersion";
+
+TEST(PreviousSessionInfoTest, InitializationWithEmptyDefaults) {
+  [PreviousSessionInfo resetSharedInstanceForTesting];
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults removeObjectForKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+  [defaults removeObjectForKey:kLastRanVersion];
+
+  // Instantiate the PreviousSessionInfo sharedInstance.
+  PreviousSessionInfo* sharedInstance = [PreviousSessionInfo sharedInstance];
+
+  // Checks the default values.
+  EXPECT_FALSE([sharedInstance didSeeMemoryWarningShortlyBeforeTerminating]);
+  EXPECT_TRUE([sharedInstance isFirstSessionAfterUpgrade]);
+}
+
+TEST(PreviousSessionInfoTest, InitializationWithSameVersionNoMemoryWarning) {
+  [PreviousSessionInfo resetSharedInstanceForTesting];
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults removeObjectForKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+  [defaults removeObjectForKey:kLastRanVersion];
+
+  // Set the current version as the last ran version.
+  NSString* currentVersion = base::SysUTF8ToNSString(
+      ios::GetChromeBrowserProvider()->GetVersionNumber());
+  [defaults setObject:currentVersion forKey:kLastRanVersion];
+
+  // Instantiate the PreviousSessionInfo sharedInstance.
+  PreviousSessionInfo* sharedInstance = [PreviousSessionInfo sharedInstance];
+
+  // Checks the values.
+  EXPECT_FALSE([sharedInstance didSeeMemoryWarningShortlyBeforeTerminating]);
+  EXPECT_FALSE([sharedInstance isFirstSessionAfterUpgrade]);
+}
+
+TEST(PreviousSessionInfoTest, InitializationWithSameVersionMemoryWarning) {
+  [PreviousSessionInfo resetSharedInstanceForTesting];
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults removeObjectForKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+  [defaults removeObjectForKey:kLastRanVersion];
+
+  // Set the current version as the last ran version.
+  NSString* currentVersion = base::SysUTF8ToNSString(
+      ios::GetChromeBrowserProvider()->GetVersionNumber());
+  [defaults setObject:currentVersion forKey:kLastRanVersion];
+
+  // Set the memory warning flag as a previous session would have.
+  [defaults setBool:YES forKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+
+  // Instantiate the PreviousSessionInfo sharedInstance.
+  PreviousSessionInfo* sharedInstance = [PreviousSessionInfo sharedInstance];
+
+  // Checks the values.
+  EXPECT_TRUE([sharedInstance didSeeMemoryWarningShortlyBeforeTerminating]);
+  EXPECT_FALSE([sharedInstance isFirstSessionAfterUpgrade]);
+}
+
+TEST(PreviousSessionInfoTest, InitializationDifferentVersionNoMemoryWarning) {
+  [PreviousSessionInfo resetSharedInstanceForTesting];
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults removeObjectForKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+  [defaults removeObjectForKey:kLastRanVersion];
+
+  // Set the current version as the last ran version.
+  [defaults setObject:@"Fake Version" forKey:kLastRanVersion];
+
+  // Instantiate the PreviousSessionInfo sharedInstance.
+  PreviousSessionInfo* sharedInstance = [PreviousSessionInfo sharedInstance];
+
+  // Checks the values.
+  EXPECT_FALSE([sharedInstance didSeeMemoryWarningShortlyBeforeTerminating]);
+  EXPECT_TRUE([sharedInstance isFirstSessionAfterUpgrade]);
+}
+
+TEST(PreviousSessionInfoTest, InitializationDifferentVersionMemoryWarning) {
+  [PreviousSessionInfo resetSharedInstanceForTesting];
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults removeObjectForKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+  [defaults removeObjectForKey:kLastRanVersion];
+
+  // Set the current version as the last ran version.
+  [defaults setObject:@"Fake Version" forKey:kLastRanVersion];
+
+  // Set the memory warning flag as a previous session would have.
+  [defaults setBool:YES forKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+
+  // Instantiate the PreviousSessionInfo sharedInstance.
+  PreviousSessionInfo* sharedInstance = [PreviousSessionInfo sharedInstance];
+
+  // Checks the values.
+  EXPECT_TRUE([sharedInstance didSeeMemoryWarningShortlyBeforeTerminating]);
+  EXPECT_TRUE([sharedInstance isFirstSessionAfterUpgrade]);
+}
+
+TEST(PreviousSessionInfoTest, BeginRecordingCurrentSession) {
+  [PreviousSessionInfo resetSharedInstanceForTesting];
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults removeObjectForKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+  [defaults removeObjectForKey:kLastRanVersion];
+
+  // Set the memory warning flag as a previous session would have.
+  [defaults setBool:YES forKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+
+  [[PreviousSessionInfo sharedInstance] beginRecordingCurrentSession];
+
+  // Check that the version has been updated.
+  EXPECT_NSEQ(base::SysUTF8ToNSString(
+                  ios::GetChromeBrowserProvider()->GetVersionNumber()),
+              [defaults stringForKey:kLastRanVersion]);
+
+  // Check that the memory warning flag has been reset.
+  EXPECT_FALSE(
+      [defaults boolForKey:kDidSeeMemoryWarningShortlyBeforeTerminating]);
+}
+
+TEST(PreviousSessionInfoTest, SetMemoryWarningFlagNoOpUntilRecordingBegins) {
+  [PreviousSessionInfo resetSharedInstanceForTesting];
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults removeObjectForKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+  [defaults removeObjectForKey:kLastRanVersion];
+
+  // Call the flag setter.
+  [[PreviousSessionInfo sharedInstance] setMemoryWarningFlag];
+
+  EXPECT_FALSE(
+      [defaults boolForKey:kDidSeeMemoryWarningShortlyBeforeTerminating]);
+}
+
+TEST(PreviousSessionInfoTest, ResetMemoryWarningFlagNoOpUntilRecordingBegins) {
+  [PreviousSessionInfo resetSharedInstanceForTesting];
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults removeObjectForKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+  [defaults removeObjectForKey:kLastRanVersion];
+
+  // Set the memory warning flag as a previous session would have.
+  [defaults setBool:YES forKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+
+  // Call the memory warning flag resetter.
+  [[PreviousSessionInfo sharedInstance] resetMemoryWarningFlag];
+
+  EXPECT_TRUE(
+      [defaults boolForKey:kDidSeeMemoryWarningShortlyBeforeTerminating]);
+}
+
+TEST(PreviousSessionInfoTest, MemoryWarningFlagMethodsAfterRecordingBegins) {
+  [PreviousSessionInfo resetSharedInstanceForTesting];
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults removeObjectForKey:kDidSeeMemoryWarningShortlyBeforeTerminating];
+  [defaults removeObjectForKey:kLastRanVersion];
+
+  // Launch the recording of the session.
+  [[PreviousSessionInfo sharedInstance] beginRecordingCurrentSession];
+
+  EXPECT_FALSE(
+      [defaults boolForKey:kDidSeeMemoryWarningShortlyBeforeTerminating]);
+
+  // Call the memory warning flag setter.
+  [[PreviousSessionInfo sharedInstance] setMemoryWarningFlag];
+
+  EXPECT_TRUE(
+      [defaults boolForKey:kDidSeeMemoryWarningShortlyBeforeTerminating]);
+
+  // Call the memory warning flag resetter.
+  [[PreviousSessionInfo sharedInstance] resetMemoryWarningFlag];
+
+  EXPECT_FALSE(
+      [defaults boolForKey:kDidSeeMemoryWarningShortlyBeforeTerminating]);
+}
+
+}  // namespace