Adds support for running unittests using XCTest on iOS.

base/test/test_support_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/test_support_ios.h"
+
 #import <UIKit/UIKit.h>
 
 #include "base/debug/debugger.h"
 #include "base/logging.h"
 #include "base/mac/scoped_nsautorelease_pool.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_pump_default.h"
 #include "base/test/test_suite.h"
 #include "testing/coverage_util_ios.h"
@@ skipping 133 matching lines @@
     NSLog(@"Writing contents of %@ to NSLog", path);
     for (NSString* line in lines) {
       NSLog(@"%@", line);
     }
   }
 }
 
 - (void)runTests {
   int exitStatus = g_test_suite->Run();
 
+  if (base::IsRunningWithXCTest()) {
+    // Do not kill the app when running in XCTest mode.  XCTest will shut down
+    // the app itself.
+    return;
+  }
+
   if ([self shouldRedirectOutputToFile])
     [self writeOutputToNSLog];
 
   // 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(crbug.com/137010): Figure out how much time is actually needed, and
   // sleep only to make sure that much time has elapsed since launch.
   [NSThread sleepUntilDate:[NSDate dateWithTimeIntervalSinceNow:2.0]];
   window_.reset();
 
@@ skipping 42 matching lines @@
   static bool ran_hook = false;
   if (!ran_hook) {
     ran_hook = true;
     mac::ScopedNSAutoreleasePool pool;
     int exit_status = UIApplicationMain(g_argc, g_argv, nil,
                                         @"ChromeUnitTestDelegate");
     exit(exit_status);
   }
 }
 
+bool IsRunningWithXCTest() {
+  // Under Xcode 7.3 and 8.0, the "XCTestConfigurationFilePath" environment
+  // variable is set when running XCTests.
+  NSDictionary* environment = [[NSProcessInfo processInfo] environment];

[Mark Mentovai, 2016/08/08 20:55:44]

  return getenv("XCTestConfigurationFilePath") != nullptr;

is less wordy and faster

[rohitrao (ping after 24h), 2016/08/09 11:40:23]

Done.

+  return environment[@"XCTestConfigurationFilePath"] != nil;
+}
+
 }  // namespace base