Tests are generally organized following the structure of the Java API. For
example, the test directory contains a java directory
that has subdirectories lang, io, util,
etc.
Each package directory contains one subdirectory for each class in the
package. Thus tests for java.io.FileInputStream can be found in
java/io/FileInputStream.
Each class directory may contain a combination of single-file tests and further subdirectories for tests that require more than one source file.