Unit Testing in Xcode, does it run the app? - iphone

Question

I'm running into a strange problem that I haven't run into before.
When you do cmd+U to run your Unit Tests (OCUnit for example) does it actually call the main.m, new up the appDelegate and run the app as if your had pressed cmd+R?
I only ask because I'm using CoreData behind this DataLayer. I'm mocking out the DataLayer successfully in my tests, but once I implemented a getAll method that is actually calling CoreData, the app/xcode is throwing an exception about the managed object model can't be nil. Which I understand, but I'm not meaning to actually new up the DataLayer class, and I've put a break point in my mainviewcontroller loadView method where it is calling the DataLayer getAll method. It shouldn't matter with tests because this is a mock object, but it's apparently calling the real instance.
So back to my question, when pressing cmd+U does it also run the app first then run the tests?

Answer 1

The application is actually run but there is a trick you can use to prevent it from running.
int main(int argc, char* argv[]) {
int returnValue;
#autoreleasepool {
BOOL inTests = (NSClassFromString(#"SenTestCase") != nil
|| NSClassFromString(#"XCTest") != nil);
if (inTests) {
//use a special empty delegate when we are inside the tests
returnValue = UIApplicationMain(argc, argv, nil, #"TestsAppDelegate");
}
else {
//use the normal delegate
returnValue = UIApplicationMain(argc, argv, nil, #"AppDelegate");
}
}
return returnValue;
}

Answer 2

Here's a variation of Sulthan's answer that uses XCTest, which is the default for test classes generated by XCode 5.
int main(int argc, char * argv[])
{
#autoreleasepool {
BOOL runningTests = NSClassFromString(#"XCTestCase") != nil;
if(!runningTests)
{
return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
}
else
{
return UIApplicationMain(argc, argv, nil, #"TestAppDelegate");
}
}
}
This goes into main.m, which should be under Supporting Files in a standard project layout.
Then in your tests directory add:
TestAppDelegate.h
#import <Foundation/Foundation.h>
#interface TestAppDelegate : NSObject<UIApplicationDelegate>
#end
TestAppDelegate.m
#import "TestAppDelegate.h"
#implementation TestAppDelegate
#end

Answer 3

In Swift, I prefere to bypass a normal execution path inside application: didFinishLaunchingWithOptions:
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
guard normalExecutionPath() else {
window = nil
return false
}
// regular setup
return true
}
private func normalExecutionPath() -> Bool {
return NSClassFromString("XCTestCase") == nil
}
Code inside guard will remove any views created from storyboard.

Answer 4

If you're using Swift (you probably don't have a main.c), you have to do these steps :
1: remove #UIApplicationMain in AppDelegate.swift
2: Create an empty TestingAppDelegate.swift
import UIKit
class TestingAppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
}
3: Create a file called main.swift :
import Foundation
import UIKit
let isRunningTests = NSClassFromString("XCTestCase") != nil
if isRunningTests {
UIApplicationMain(C_ARGC, C_ARGV, nil, NSStringFromClass(TestingAppDelegate))
} else {
UIApplicationMain(C_ARGC, C_ARGV, nil, NSStringFromClass(AppDelegate))
}

Answer 5

I found another solution to the problem:
int main(int argc, char * argv[])
{
#autoreleasepool {
return UIApplicationMain(argc, argv, nil, ({
![NSProcessInfo processInfo].environment[#"XCTestConfigurationFilePath"] ?
#"AppDelegate" :
nil;
}));
}
}
From here: http://qualitycoding.org/app-delegate-for-tests/#comment-63984

Answer 6

Using xCode 7 and xCtool
xctool is capable of executing unit tests without running the app.
To get this working,
1 . Update target settings to run without a host app.
Select your project --> then test target --> Set the host application to none.
2. Install xctool , if you don't have it.
brew install xctool
3. Run the tests using terminal with xctool.
xctool -workspace yourWorkspace.xcworkspace -scheme yourScheme run-tests -sdk iphonesimulator

Answer 7

You can do that by setting the Host Application to None in your Tests Target.

Answer 8

Yes, your test target will have a target dependency to the app target, so the app target will be built when you press Cmd+U or Cmd+Shift+U.

Answer 9

Excellent answers above that suggest dynamically changing the application delegate at run time.
The small modification I make is to detect a unit test run by querying NSProcessInfo. The advantage is that you don't need to have a class that can be detected to see if unit tests are running.
int main(int argc, char * argv[])
{
// Put your App delegate class here.
const Class appDelegateClass = [ATAppDelegate class];
NSDictionary *const environmentDictionary =
[[NSProcessInfo processInfo] environment];
const BOOL runningUnitTests =
environmentDictionary[#"XCInjectBundleInto"] != nil;
NSString *delegateName =
runningUnitTests ? nil : NSStringFromClass(appDelegateClass);
#autoreleasepool {
return UIApplicationMain(argc, argv, nil, delegateName);
}
}
The #"XCInjectBundleInto" property in environmentDictionary is the path to your unit tests bundle and is set up by Xcode.

Answer 10

I use the approach of Tomasz Bak plus some code of dwb answer and come up with the following:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
BOOL runningTests = NSClassFromString(#"XCTestCase") != nil;
if (runningTests) {
self.window.rootViewController = [UIViewController new];
return true;
}
// Your normal code below this
....
}