Improve tests.

[jhlegarreta]

The existing tests should be improved:

• ITK testing conventions on the naming of the test files should be applied.
• The ITK testing macros should be used (e.g. TRY_EXPECT_NO_EXCEPTION, EXERCISE_BASIC_OBJECT_METHODS, etc.) to avoid boilerplate code.
• The tests should run as long as possible and return the status code at the end (i.e. use a testStatus in and change its value as tests fail: requires changing the test design).
• The coding style should conform to the ITK coding style (Appendix Three).