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Code Coverage for Gradle Java Projects

Integrate RKTracer with gradle build and generate code coverage

You need to build and test the application with gradle build.RKTracer tool will automatically add a runtime library to the application when you integrate and build the application with the RKTracer tool.

To instrument with the RKTracer tool, you need to enable RKTracer before running the gradle build command to build the application. You should always rebuild the project to instrument application with the RKTracer tool.

gradle build

Enable RKTracer tool “rktracer gradle -on build.gradle”

gradle rebuild

RKTracer tool makes internal adjustments to gradle build to instrument all the source files compiled at build time. By default, rktracer instruments for multiple-condition code coverage, and you see the following code coverage information in the HTML report.

  • Function Coverage
  • Line Coverage 
  • Statement Coverage
  • Multi-Condition Code Coverage
 

Example Gradle build

Step 1: Enable RKTracer Tool and rebuild the application.

 
  • RKTracer instruments the preprocessed file with “c:\rktracer/lib/librklij-x86_64-w64-mingw32.exe ” and writes out the instrumented file the “prime.java” file in the preprocessed directory. Also, it stores the metadata, structure of instrumentation, and copy of source file content in JSON file. The tool will refer rktracer.config for internal configuration at the time of instrumentation.
  • RKTracer automatically adds runtime at linking time.
 

Step 2: Test instrumented application. 

When you run unit tests or functional testing the RKTracer tool will save coverage data to the rk-coverage.txt file on the host or phone device. If your running unit tests on the host and see the rk-coverage.txt file you can jump to the third step to generate code coverage html reports. 

If your doing unit or functional testing on a phone device, then you need to Install the rktracer instrumented APK in the phone device(don’t disconnect the device from the host machine) execute the command by opening the command prompt or terminal from the application working directory, i.e., parallel to the rktracer folder(rktracer folder will get generate once we instrument the application with rktracer tool). So that coverage data from logcat will get collected from the device. Then start testing the app on the device.

adb -e logcat > rk-coverage.txt 2>&1

The above command will write code coverage data from logcat to the rk-coverage.txt file. You should not change the file name, i.e., rk-coverage.txt as the RKTracer tool will consider the rk-coverage.txt file as a coverage data file. By default, the rktracer tool will save coverage data in the phone device, you check this in logcat output. Here is the sample logcat output for the keyword “rk-coverage.”

2021-05-19 20:17:39.947 1203-4189/com.google.android.gms I/SQLiteCastStore: [CastNetworkInfo] saved: 0, skipped: 0, [CastDeviceInfo]: saved 0, skipped 1, [Paired Guest Mode DeviceInfo] saved: 0, skipped: 0. [ProbedNetworks]: saved 0, skipped: 0, [ProbedSocketAddress]: saved 0, skipped: 0, [Network-Device pairs]: saved: 0

2021-05-19 20:17:58.173 4718-4753/? I/rktracer: ‘/sdcard/rk-coverage.txt’ Operation not permitted

2021-05-19 20:17:58.174 4718-4753/? I/rktracer: writing to ‘/data/data/com.example.widecolor/rk-coverage.txt’

2021-05-19 20:26:39.240 5053-5084/? I/rktracer: ‘/sdcard/rk-coverage.txt’ Operation not permitted

2021-05-19 20:26:39.241 5053-5084/? I/rktracer: writing to ‘/data/data/com.example.widecolor/rk-coverage.txt’

2021-05-19 20:27:39.428 5181-5207/? I/rktracer: ‘/sdcard/rk-coverage.txt’ Operation not permitted

2021-05-19 20:27:39.428 5181-5207/? I/rktracer: writing to ‘/data/data/com.example.widecolor/rk-coverage.txt’

To pull the coverage data, you can execute the command. 

adb pull  /data/data/com.example.widecolor/rk-coverage.txt 

We need to copy the pulled rk-coverage.txt file to the application folder where we have the rktracer folder in the application directory.

Coverage data file not found after testing.

RKTracer tool uses the following approaches to save coverage data.

  • Run unit/functional testing, and at the end RKTracer tool will automatically save coverage data on the host/embedded target/server machine, that is, write coverage data to the rk-coverage.txt file.
  • Send a signal to the application running in an infinite loop to trigger and save coverage data. 
  • The application under test has crashed in the middle of testing on the host or target device. RKTracer saves coverage data to rk-coverage.txt and generate reports to check the point of a crash in reports.
  • Embedded devices without a file system or not connected to host while testing. In this case, rktracer RAW mode comes in to picture. You need to save the coverage data from the RKTracer variable. 

Suppose you cannot find the rk-coverage.txt file in the project working folder or target server machine. An application under test has not exited within the proper shutdown hook, i.e., Runtime. get runtime().addShutdownHook(new Thread()), or your application might be running in an infinite loop or live application

Save coverage data when a particular function is executed at runtime testing.

Identify a function/method name in your application (ensure this function/method is not excluded from RKTracer instrumentation or file with this function). Then copy the function name and edit the rktracer.config in the RKTracer installation folder. 

For Java programming language:  Add a new line at the end of rktracer.config file with “java-function-writeout” and function name. Here the function name is case sensitive, and you should also add empty braces, i.e., () at the end of a function name. In case if you have a function with an input parameter, it should still be empty braces. You can add multiple function names with one space to the list, as shown below.

  • java-function-writeout main()
  • java-function-writeout main()  OnCreate() fun()

For Kotlin programming language: Add a new line at the end of rktracer.config file with “kotlin-function-writeout” and function name. Here the function name is case sensitive, and you should also add empty braces, i.e., () at the end of a function name. In case if you have a function with an input parameter, it should still be empty braces. You can add multiple function names with one space to the list, as shown below.

  • kotlin-function-writeout main()
  • kotlin-function-writeout main()  OnCreate() fun()

After adding function name to rktracer.config file. You need to rebuild the application to re-instrument using rktracer. Coverage data will be saved to the rk-coverage.txt file when this function executes at runtime testing. 

Send a signal to save coverage data.

We can send a signal to the application running in an infinite loop to save coverage data to rk-coverage.txt.

  • Windows: send a kill signal using keys in the keyboard, i.e., Control+Pause/break. Contact support if you would like to add additional signal command to save coverage data at runtime testing.
  • Linux/Unix: Send a SIGWINCH signal: killall -SIGWINCH a.out or kill -SIGWINCH Process ID number.

Step 3: Generate Code Coverage HTML reports.

Open a terminal or command prompt in the application directory where have the rktracer folder and execute the following command to generate reports.

 Linux: “rkresults app/build.gradle” to generate reports. 

Windows: “rkresults app\build.gradle” to generate reports. 

If the RKTracer Html reports are not opening in the browser, we can navigate the project folder/rktracer/reports/ and open index.html to check the reports.

 

NOTE: Once the reports are generated, you need to disable the RKTracer tool with “rktracer gradle -off  build.gradle”

Generate code coverage for selected functions/files/folder

Generate coverage reports  for the selected folders

C:\project\sound\drivers\base\power\

C:\project\sound\drivers\base\power\firmware_loader\

C:\project\sound\drivers\core\

C:\project\sound\security\keys\

C:\project\sound\security\lockdown\

 

Suppose you need code coverage for source files from three different folders, i.e., core, keys, power, and ignore coverage for folders firmware_loader and lockdown. Edit rktracer.config in the RKTracer installation folder and go to the end of the file add the following information. 

ignore *.java

instrument */power/* */core/* */keys/*

never */firmware_loader/* */lockdown/*

 

ignore *.java = Ignores all Java source files from instrumentation

Instrument = Instrument source files from given folders

never = ignore selected folder  

        

Generate coverage reports only for selected functions from three different files.

fun_X() in source-file-X 

fun_Y() in source-file-Y

fun_Z() in source-file-Z

Suppose you need code coverage for selected functions from three different files. Edit rktracer.config in the RKTracer installation folder and go to the end of the file and set the following variables as shown below.  

ignore *.java

instrument *source-file-X.java *source-file-Y.java *source-file-Z.java

function-ignore *

function-instrument fun_X() fun_Y() fun_Z()

 

ignore *.java = Ignore all Java programming source files

instrument *file-X.java  *file-Y.java  *file-Z.java  = Instrument only these three source files.

function-ignore * = Then ignore all functions in the above three files.

function-instrument fun_X() fun_Y() fun_Z() = Don’t ignore these three functions from these three files from instrumentation

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