Iphone Unit testing

http://code.google.com/p/google-toolbox-for-mac/wiki/iPhoneUnitTesting

Introduction

This is a quick tutorial on doing iPhone unit testing using the facilities in the Google Toolbox For Mac. Please send mail to the group if any clarification is required.

Basic Project Setup

Hopefully your project already has an application target for building something for the iPhone.

  1. Create a new iPhone Target of type “Cocoa Touch Application” via “Project Menu > New Target…”. Choose a name that makes some sense such as “Unit Test”. Be sure to use a “Cocoa Touch Application” target as opposed to a “Cocoa Application” target or a “Cocoa Touch Static Library” target or “Cocoa Touch Unit Test Bundle”.
  2. Add google-toolbox-for-mac/UnitTesting/GTMIPhoneUnitTestMain.m to your target
  3. Add google-toolbox-for-mac/UnitTesting/GTMIPhoneUnitTestDelegate.m to your target
  4. Add google-toolbox-for-mac/UnitTesting/GTMIPhoneUnitTestDelegate.h to your project
  5. Add google-toolbox-for-mac/UnitTesting/GTMSenTestCase.m to your target
  6. Add google-toolbox-for-mac/UnitTesting/GTMSenTestCase.h to your project
  7. Add google-toolbox-for-mac/UnitTesting/GTMUnitTestDevLog.m to your target
  8. Add google-toolbox-for-mac/UnitTesting/GTMUnitTestDevLog.h to your project
  9. Add google-toolbox-for-mac/Foundation/GTMObjC2Runtime.m to your target
  10. Add google-toolbox-for-mac/Foundation/GTMObjC2Runtime.h to your project
  11. Add google-toolbox-for-mac/Foundation/GTMRegex.m to your target
  12. Add google-toolbox-for-mac/Foundation/GTMRegex.h to your project
  13. Add google-toolbox-for-mac/GTMDefines.h to your project
  14. Add a new ‘run script’ build phase as the last step of your target build via “Project Menu > New Build Phase > New Run Script Build Phase”, and dragging it to the end of the build steps if needed.
  15. Edit your Run Script Build Phase by double clicking it, and set the shell to “/bin/sh” and the script to"PATH_TO_GTM/UnitTesting/RunIPhoneUnitTest.sh", where PATH_TO_GTM is the path to your local version of google-toolbox-for-mac.
  16. Xcode’s new application stationery generates an Info.plist that specifies a Main nib file base name. Open the new unit test’s .plist file and remove that line. If you don’t do this, RunIPhoneUnitTest.sh will crash when UIApplication throws an exception trying to load an inappropriate or non-existent nib file.
  17. Build! Note that if you choose build and go you will see your unit tests executed twice, once as part of the build script, and once being run

 

Your target should now build cleanly, and if you check the build log you should see something like: “Executed 0 tests, with 0 failures (0 unexpected) in 0.001 (0.001) seconds” at the end.

Trouble Shooting

  • Make sure you are not linked against the SenTestingKit.framework.

Creating a unit test

  1. Add the source you want to test to your target. For example if you want to test class Foo, make sure to add Foo.h and Foo.m to your target.
  2. Add a new unit test file to your target via “File > New File” and choose “Objective-C test case class” from the “Mac OS X” Cocoa category. Call it FooTest.m, or follow whatever convention your project has for naming test classes.
  3. In FooTest.h, change #import <SenTestingKit/SenTestingKit.h> to #import "GTMSenTestCase.h"
  4. Also set up your class so that it inherits from GTMTestCase (not GTMSenTestCase) instead of SenTestCase
    @interface MyTestCase : GTMTestCase { ... }
  5. Add test cases as you normally would. See Apple’s Documentation for a good tutorial on how to test in Objective C. The key is that your test case methods are declared - (void)testBar. The name must start with “test” and they must return nothing and have no arguments.

Now when you build your target you should now see test cases executing. You can repeat this process creating additional source files for each class you want to write Unittests for.

Debugging

You can debug your unit test executable the exact same way you would unit test any executable. You shouldn’t have to set up anything. Note that you may see cases where the unit test build fails, but it doesn’t fail when you are debugging. When the unit test build is running several flags are turned on to encourage failures such as MallocScribbleNSAutoreleaseFreedObjectCheckEnabled etc. You may want to look inRunIPhoneUnitTest.sh and see what is being enabled for you.

Notes

  • We find that having a .h for tests to be mostly useless, and tend to just the interfaces for the tests in with the implementation so I only have one file to worry about.
  • Make sure to check out the extra ST macros that we have added in GTMSenTestCase.h that go above and beyond the set included with the default OCUnit.
    • STAssertNoErr(a1, description, …), STAssertErr(a1, a2, description, …)
    • STAssertNotNULL(a1, description, …), STAssertNULL(a1, description, …)
    • STAssertNotEquals(a1, a2, description, …), STAssertNotEqualObjects(a1, a2, desc, …)
    • STAssertEqualObjects(a1, a2, description, …), STAssertEquals(a1, a2, description, …), STAssertEqualsWithAccuracy(a1, a2, accuracy, description, …)
    • STAssertOperation(a1, a2, op, description, …), STAssertGreaterThan(a1, a2, description, …), STAssertLessThan(a1, a2, description, …), STAssertLessThanOrEqual(a1, a2, description, …)
    • STAssertEqualStrings(a1, a2, description, …), STAssertNotEqualStrings(a1, a2, description, …), STAssertEqualCStrings(a1, a2, description, …), STAssertNotEqualCStrings(a1, a2, description, …)
    • STAssertTrueNoThrow(expr, description, …), STAssertFalseNoThrow(expr, description, …), STAssertThrows(expr, description, …), STAssertThrowsSpecific(expr, specificException, description, …), STAssertThrowsSpecificNamed(expr, specificException, aName, description, …), STAssertNoThrow(expr, description, …), STAssertNoThrowSpecific(expr, specificException, description, …), STAssertNoThrowSpecificNamed(expr, specificException, aName, description, …)
  • You can’t run the build script while the iPhone simulator is running. The build script does attempt to kill it off before it runs, but if you seeCouldn't register PurpleSystemEventPort with the bootstrap server. Error: unknown error code. This generally means that another instance of this process was already running or is hung in the debugger. or Abort trap "$TARGET_BUILD_DIR/$EXECUTABLE_PAT" -RegisterForSystemEvents you probably need to figure out why the simulator (or another iPhone process) is already running. The exact error has changed with different versions of the iPhone SDK.

Advanced Stuff

Unit test Logging

When Unittesting is done correctly, you often have a lot of log messages logging because you are testing edge cases that you may not expect to hit in the real world very often. It’s nice to be able to verify that the log messages you are receiving as you run your tests are the ones that you expect to receive. You can do this in GTM by enabling unit test logging.

  1. Assuming you are using _GTMDevLog to do your logging,#define _GTMDevLog _GTMUnittestDevLog somewhere, either in target settings, or in your prefix. If you are using NSLog you can just define it to be _GTMUnittestDevLog.
  2. Add google-toolbox-for-mac/DebugUtils/GTMDevLog.m to your target.
  3. Add google-toolbox-for-mac/UnitTesting/GTMUnitTestDevLog.m to your target.
  4. Add google-toolbox-for-mac/Foundation/GTMRegex.m to your target.
  5. You may also need to add some headers depending on your search paths

Now when you build all of the logging that you do via your unit tests will get checked to make sure that it conforms with your expectations. You set up these expectations before running your tests using [GTMUnitTestDevLog expect*] methods. See GTMUnitTestDevLog.h for more info.

UI and State Testing

GTM can also help you test your UI’s representation and state.

  1. Add google-toolbox-for-mac/UnitTesting/GTMNSObject+UnitTesting.m to your target.
  2. Add google-toolbox-for-mac/UnitTesting/GTMUIKit+UnitTesting.m to your target.
  3. Add google-toolbox-for-mac/UnitTesting/GTMCALayer+UnitTesting.m to your target.
  4. Add google-toolbox-for-mac/Foundation/GTMSystemVersion.m to your target.
  5. Add the CoreGraphics and QuartzCore frameworks to your target.
  6. You may also need to add some headers depending on your search paths

Check out UnitTesting/GTMUIKit+UnitTestingTest.m for examples of using UIUnitTesting on the iPhone.

For more information on some of this, check out CodeVerificationAndUnitTesting. Hope this helps.

Unit Test Environment Variables

To encourage “bad behavior” by the code being tested, the RunIPhoneUnitTest.sh script sets a variety of environment variables. If you are wondering why the unit tests fail when you are building, but don’t fail when you are running, it may be because of a side effect of one of these variables. Take a look at all the export commands within RunIPhoneUnitTest.sh to see what’s actually going on.

Leaks

By default the iPhone unit tests will run leaks after all the tests have completed. This can be turned off by setting the GTM_DISABLE_LEAKSenvironment variable before you execute the RunIPhoneUnitTest.sh script. Out of the box, NSZombies will also be enabled. This however interferes slightly with leaks and makes it difficult to get good backtraces and context. If you want the backtraces and context, set theGTM_DISABLE_ZOMBIES environment variable before you execute the RunIPhoneUnitTest.sh script. All leaks will appear as warnings on the build console.

Termination

Some of Apple’s tools (such as Instruments) don’t want the app to terminate underneath them. By default the iPhone unit test app will terminate when it has finished it’s run. Set the GTM_DISABLE_TERMINATION environment variable if you want to disable termination and just have the unit test “run” until you are done with it.

Keychain Testing

If your code uses the keychain, you may need to set GTM_DISABLE_IPHONE_LAUNCH_DAEMONS=0 before you run your unit tests. See RunIPhoneUnitTest.sh for details on this flag and why it should be set.

 

What Are Your Options?

Before you decide how to present your product to iPhone OS users, you need to understand the range of options you have. Depending on the implementation details of your proposed product and its intended audience, some types of software may be better suited to your needs than others.

This section divides software for iPhone OS–based devices into three broad categories, primarily based on implementation method. Roughly speaking, you can create:

An iPhone application, which is an application you develop using the iPhone SDK to run natively on iPhone OS–based devices.

Web-only content, including web applications, which are websites that behave like built-in iPhone applications.

A hybrid application, which is an iPhone application that provides access to web content primarily through a web-content viewing area, but includes some iPhone OS user interface elements.

iPhone Applications

iPhone applications resemble the built-in applications on iPhone OS–based devices in that they reside on the device itself and take advantage of features of the iPhone OS environment. Users install iPhone applications on their devices and use them just as they use built-in applications, such as Stocks, Maps, Calculator, and Mail.

An iPhone application is quick to launch and easy to use. Whether the application enables a task like sending email or provides entertainment to users, it is characterized by responsiveness, simplicity, and a beautiful, streamlined user interface.

Web-only Content

You have a few different options when it comes to providing web-only content to iPhone OS users:

Web applications

as web applications, because they behave similarly to the built-in iPhone OS applications. A web application, like all web-only content, runs in Safari on iPhone; users do not install it on their devices, instead they go to the web application’s URL.

Optimized webpages

Webpages that are optimized for Safari on iPhone display and operate as designed (with the exception of any elements that rely on unsupported technologies, such as plug-ins, Flash, and Java). In addition, an optimized webpage correctly scales content for the device screen and is often designed to detect when it is being viewed on iPhone OS–based devices, so that it can adjust the content it provides accordingly.

Compatible webpages

Webpages that are compatible with Safari on iPhone display and operate as designed (with the exception of any elements that rely on unsupported technologies, such as plug-ins, Flash, and Java). A compatible webpage does not tend to take extra steps to optimize the viewing experience on iPhone OS–based devices, but the device usually displays the page successfully. If you have an existing website or web application, first ensure that it works well on iPhone OS–based devices.

Also, you should consider creating a custom icon users can put on their Home screens using the Web Clip feature. In effect, this allows users to keep on their Home Screens a bookmark to your website that looks like a native application icon. To learn more about creating a custom icon and how to make web content look great on iPhone OS–based devices, see iPhone Human Interface Guidelines for Web Applications.

Hybrid Applications

With iPhone OS, you can create an application that combines features of native applications and webpagesA hybrid application is a native iPhone application that provides most of its structure and functionality through a web viewing area, but also tends to contain standard iPhone OS user interface elements.

A hybrid application gives users access to web content with an element called a web view Precisely how you use a web view in your application is up to you, but it’s important to avoid giving users the impression that your application is merely a mini web browser. A hybrid application should behave and appear like a native iPhone application; it should not draw attention to the fact that it depends upon web sources.