Created some Java tests to verify that the library can be called from Java code
moved test data to a separate class so it's easier to re-use in the Java tests, and created a TestData class so it's easier to use in Java (IntelliJ didn't like the Pair class for some reason, and kept showing errors for data.getFirst())
Enabled JUnitPlatform (otherwise the JUnit classes weren't available in the jvmTest source set)
data.getFirst())Related to #12