Add unit tests for NFA and NFAImpl

[GoogleCodeExporter]

Convertion algorithm is very hard to test in black box test. Since the
outcome of the algorithm cannot be expressed clearly in words. So one
cannot setup criterion for the test. The only way to test this algorithm is
by using an equality test on the NFA and the result DFA. But the problem is
that it's really hard to define what such "equality" is.

A few sample test cases should be sufficient for the white box test. Focus
more on the coverage is more pragmatic than to "prove" the correctness of
the implementation.

If bugs are to be found, we shall easily add more test cases and fix those
bugs.

Original issue reported on code.google.com by lemontree.cool on 6 Sep 2008 at 2:58

[GoogleCodeExporter]

Original comment by lemontree.cool on 6 Sep 2008 at 3:04

• Changed state: Accepted

[GoogleCodeExporter]

Original comment by lemontree.cool on 13 Sep 2008 at 12:41

• Changed state: Fixed