[MUSIC] 0:00 We've just finished using the Kito to unit test our app. 0:04 But now it's time to see what's so special about Robolectric. 0:08 To quote their website, Robolectric it is a unit test framework that defangs 0:11 the Android S.T.K. jar so you can test drive the development of your Android app. 0:17 Remember earlier when we were trying to start our activity and it didn't work. 0:22 Roboelectric aims to fix that by rewriting the Android classes 0:27 as they're being loaded making it possible for 0:31 them to run on your computer just like any other Java application. 0:34 First things first we need to add Roboelectric as a dependency. 0:39 Let's head over to our build.gradle file and add it. 0:43 It's in the teacher's notes below. 0:47 Then hit Sync Now and we're good to go. 0:52 Now let's get started with Robolectric by switching back to our main activity 1:00 test class. 1:04 Then let's comment out the lines in both the set up and 1:07 editTextUpdatesTextView methods. 1:10 Just like when we use my Kito we need to be sure that we're using the correct 1:19 test runner. 1:24 Let's add a run with annotation right above our class declaration 1:25 and then pass an Alt+enter to import it, and 1:33 we're passing in RobolectricGradleTestRunner.class. 1:37 At this point if we right click and 1:41 try to run main activity test, we'll get an error. 1:47 Field constants not specified in @Config annotation. 1:53 This is required when using RobolectricGradleTestRunner! 1:59 So right below our RunWith annotation, let's add the Config annotation. 2:03 And inside the parentheses, 2:13 let's specify the Constants field and 2:17 set it equal to BuildConfig.class. 2:23 Roboelectric use the build config class to figure out how to access our manifest, 2:29 resources and assets. 2:34 So it's important we add that. 2:36 Roboelectric would have a tough time being useful without knowing where anything is. 2:39 Now that we've specified the constants field, let's try running this again. 2:44 Darn another error. 2:51 Turns out Roboelectric doesn't yet support A.P.I. level twenty three. 2:53 Luckily we can fix this pretty easily 2:58 by adding another field to our config annotation. 3:01 After Bill.class let's add 3:05 comma Sdk equals Build.VERSION_CODES and 3:10 Alt+Enter to import build .LOLLIPOP. 3:19 Then let's try running it again. 3:26 And after it finishes downloading some things, success! 3:36 But why do we need to use Lollipop? 3:43 Why can't we just use Marshmellow? 3:46 Well after a new version of Android is released it just takes a while for 3:49 Roboelectric to get updated. 3:53 If you're curious about why the process takes so 3:56 long, check out the GitHub issue linked in the teacher's notes below. 3:58 Also the newest version of Roboelectric might just work with Marshmellow. 4:02 It just isn't officially released yet but that doesn't mean we can't use it. 4:07 Over on our build.gradle file, 4:13 let's change 3.0 to 3.1-SNAPSHOT. 4:18 A snapshot build represents the most recent changes and 4:27 isn't considered a stable release. 4:31 To use this snapshot build, 4:34 we'll also need to add a repository section above the dependency section. 4:35 Let's copy it in from the teacher's notes below and 4:41 then paste it right above the word dependencies. 4:45 Then let's sync the project and now thanks to our new snapshot 4:49 build we should be able to safely remove the SDK config parameter. 4:55 And it works. 5:12 Nice. We're all set up to start exploring unit 5:13 testing with Roboelectric. 5:17 In the next video, will see how to set up an activity for unit testing and 5:19 write our first Robolectric unit test. 5:23