facts about A1
more specific facts about A1
 added test facts to A2, A3.
added facts about A4
added facts about A4
added facts about A5
adds tests for A1.
adds tests for A1.
adds tests for A1.
adds tests for A1.
adds A2 tests
adds A3 tests
adds A3 tests
adds A3, A4 tests
Add exception throwing for bad R and D values"