The test_fpe and test_mark_point tests currently fail on Cygwin. Instead of the test process receiving a SIGFPE it instead fails with a SIGSEGV. The reason is not yet know. However, attempting a simple program that installs a SIGFPE handler then does a raise(SIGFPE) does result in the handler being called.

When this issue is resolved the unit tests need to be enabled for Cygwin on AppVeyor.