Make it possible to run gtests on iOS.

base/test/main_hook_ios.mm

+// 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/test/main_hook.h"
+
+#import <UIKit/UIKit.h>
+
+#include "base/debug/debugger.h"
+#include "base/logging.h"
+#include "base/mac/scoped_nsautorelease_pool.h"
+
+// Springboard will kill any iOS app that fails to check in after launch within
+// a given time. These two classes prevent this from happening.
+
+// MainHook saves the chrome main() and calls UIApplicationMain(),

[Mark Mentovai, 2012/07/12 13:37:50]

Oh, patch-cest!

[leng, 2012/07/12 15:18:06]

Stuart had to explain that to me.  :)

+// providing an application delegate class: ChromeUnitTestDelegate. The delegate
+// listens for UIApplicationDidFinishLaunchingNotification. When the
+// notification is received, it fires main() again to have the real work done.

[Mark Mentovai, 2012/07/12 13:37:50]

Give an example of usage, showing that the MainHook object should be the first
thing in main (to avoid duplicating the stuff that happens before MainHook), and
that it should be instantiated with |main, argc, argv| as arguments to its
constructor.

[leng, 2012/07/12 15:18:06]

Done.

+
+// Since the executable isn't likely to be a real iOS UI, the delegate puts up a
+// window displaying the app name. If a bunch of apps using this are being run

[Mark Mentovai, 2012/07/12 13:37:50]

“using this” isn’t clear. You mean MainHook, but I thought you meant “the
window.” Say MainHook.

[leng, 2012/07/12 15:18:06]

Done.

+// in a row, this provides an indication of which one is currently running.
+
+static MainHook::MainType g_main_func = NULL;
+static int g_argc;
+static char** g_argv;
+
+@interface ChromeUnitTestDelegate : NSObject
+- (void)runTests;
+@end
+
+@implementation ChromeUnitTestDelegate
+
+- (BOOL)application:(UIApplication *)application
+    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
+
+  CGRect bounds = [[UIScreen mainScreen] bounds];
+
+  // Yes, this is leaked, it's just to make what's running visible.

[Mark Mentovai, 2012/07/12 13:37:50]

You don’t have to leak it, and it’s easy enough to not leak it. Save it in the
object and get rid of it after g_main_func (or your sleep) in -runTests.

[leng, 2012/07/12 15:18:06]

Done.

+  UIWindow* window = [[UIWindow alloc] initWithFrame:bounds];
+  [window makeKeyAndVisible];
+
+  // Add a label with the app name.
+  UILabel* label = [[[UILabel alloc] initWithFrame:bounds] autorelease];
+  label.text = [[NSProcessInfo processInfo] processName];
+  label.textAlignment = UITextAlignmentCenter;
+  [window addSubview:label];
+
+  // Queue up the test run.
+  [self performSelector:@selector(runTests)
+             withObject:nil
+             afterDelay:0.1];
+  return YES;
+}
+
+- (void)runTests {
+  int exitStatus = g_main_func(g_argc, g_argv);
+
+  // If a test app is too fast, it will exit before Instruments has has a
+  // a chance to initialize and no test results will be seen.
+  // TODO(ios): crbug.com/137010 Figure out how much time is actually needed.
+  [NSThread sleepUntilDate:[NSDate dateWithTimeIntervalSinceNow:2.0]];

[Mark Mentovai, 2012/07/12 13:37:50]

This also adds a delay to test apps that weren’t too fast. Is it better to take
a time since start (since -application:didFinishLaunchingWithOptions: was
called) to enforce some minimum time, but not cause already long-running tests
to run even longer?

[stuartmorgan, 2012/07/12 13:41:35]

That's exactly what the TODO is for; I think we should do that as well, but
would rather not block getting tests running upstream on it.

[Mark Mentovai, 2012/07/12 14:04:09]

stuartmorgan wrote:
The TODO says “figure out how much time is needed,” not “don’t make this delay
cumulative with the time the test has already taken.”

[leng, 2012/07/12 15:18:06]

I hope the comment is clearer now.

+
+  // Use the hidden selector to try and cleanly take down the app (otherwise
+  // things can think the app crashed even on a zero exit status).
+  UIApplication* application = [UIApplication sharedApplication];
+  if ([application respondsToSelector:@selector(_terminateWithStatus:)]) {
+    [application performSelector:@selector(_terminateWithStatus:)

[Mark Mentovai, 2012/07/12 13:37:50]

Rather than using -performSelector: and this ugly (id) cast, why not provide a
declaration of the private function so you can just call it like normal:
[application _terminateWithStatus:exitStatus]?

[leng, 2012/07/12 15:18:06]

Done.

+                      withObject:(id)exitStatus];
+  }
+  exit(exitStatus);
+}
+
+@end
+
+#pragma mark -
+
+MainHook::MainHook(MainType main_func, int argc, char* argv[]) {
+  static bool ran_hook = false;
+  if (!ran_hook) {
+    ran_hook = true;
+
+    g_main_func = main_func;
+    g_argc = argc;
+    g_argv = argv;
+
+    base::mac::ScopedNSAutoreleasePool pool;
+    int exitStatus = UIApplicationMain(argc, argv, nil,

[Mark Mentovai, 2012/07/12 13:37:50]

Outside of an Objective-C section, name_variables_like_this.

[leng, 2012/07/12 15:18:06]

Done.

+                                       @"ChromeUnitTestDelegate");
+    exit(exitStatus);
+  }
+}