The text color of the widget can be customized, as well as the color and the alpha of the background. Press the result or formula in the widget to open the app.
<ahref='https://play.google.com/store/apps/details?id=com.simplemobiletools.calculator'><imgsrc='http://simplemobiletools.github.io/assets/public/google-play.png'alt='Get it on Google Play'height=45/></a>
<ahref='https://f-droid.org/app/com.simplemobiletools.calculator'><imgsrc='http://simplemobiletools.github.io/assets/public/f-droid.png'alt='Get it on F-Droid'height=45></a>
1. at Build Variants select "Android Instrumentation Tests"
2. Run -> Edit Configurations
3. create a new "Android Tests" configuration, give it a name (i.e. "MainActivityEspressoTest")
4. choose the "app" module
5. OK
6. make sure MainActivityEspressoTest is selected near the Run button
7. Run
<h3>Running Robolectric tests</h3>
1. at Build Variant select "Unit Tests"
2. at the Project tab right click the folder containing the tests (i.e. "calculator.simplemobiletools.com.simple_calculator (test)")
3. select Run 'Tests in 'calculator.simplemob...' to run all the tests
4. if you are on Linux or Mac, go to Run -> Edit Configurations, select the new JUnit configuration and change the "Working Directory" item to "$MODULE_DIR" (without quotes)