Run on Android with 1) Build the tests. 2) Install the calculator with adb install /out/target/product/generic/data/app/ExactCalculator/ExactCalculator.apk 3) adb install /out/target/product/generic/data/app/ExactCalculatorTests/ExactCalculatorTests.apk 4) adb shell am instrument -w com.android.exactcalculator.tests/android.test.InstrumentationTestRunner There are two kinds of tests: 1. A superficial test of calculator functionality through the UI. This is a resurrected version of a test that appeared in KitKat. This is currently only a placeholder for regression tests we shouldn't forget; it doesn't yet actually do much of anything. 2. A test of the BoundedRationals library that mostly checks for agreement with the constructive reals (CR) package. (The BoundedRationals package is used by the calculator mostly to identify exact results, i.e. terminating decimal expansions. But it's also used to optimize CR computations, and bugs in BoundedRational could result in incorrect outputs.) We currently have no automatic tests for display formatting corner cases. The following numbers have exhibited problems in the past and would be good to test. Some of them are difficult to test automatically, because they require scrolling to both ends of the result. For those with finite decimal expansions, it also worth confirming that the "display with leading digits" display shows an exact value when scrolled all the way to the right. Some interesting test cases: 10^10 + 10^30 10^30 + 10^-10 -10^30 + 20 10^30 + 10^-30 -10^30 - 10^10 -1.2x10^-9 -1.2x10^-8 1 - 10^-98 1 - 10^-100 1 - 10^-300 1/-56x10^18 (on a Nexus 7 sized portrait display) -10^-500 (scroll to see the 1, then scroll back & verify minus sign appears)