make test

[edlins]

HIGH priority (test is god) IN PROGRESS status

Implement test cases.

• Modify library to run on Travis CI VM (without i2c or a pca9685).
  • Provide library variables that put the library into test mode and hold an fd for test output.
  • Test mode will not open() the i2c fd but will log the attempt.
  • Test mode will not call ioctl() but will log the attempt.
• Provide a test application containing unit tests.
  • Test application will run library either in test or for real and put it "through its paces".
• cmake test invocation will run test application.
  • cmake invocation will redirect stdout to a file.
  • cmake will compare the actual output file to an expected output file, generated offline in dev.

[edlins]

Test app started. See https://github.com/edlins/libPCA9685/compare/develop...test?expand=1.

[edlins]

done with #28 and #30. continue to add tests to test app as time allows.