Building/Running the App
I recommend using Android Studio Guide.
You can also install the signed APK app/app-debug.apk
Testing
In Android Studio, right click on the test class ConverterActivityTest
and run with the Android testing framework. I don't recommend using Gradle.
The Android framework can be finicky at times, depending on the device/emulator you use. If you run into this problem, it may be best to run each test method individually.
Notes
You can pinch to zoom on the chart.