[test _test_ test](www.test.com)
[test `test` test](www.test.com)
[test *test* test](www.test.com)
[test *test* *test* test](www.test.com)
[test *test* *test* *test* test](www.test.com)
[test **test** test](www.test.com)
[test __test__ test](www.test.com)
[this should not raise](www.shouldnotraise.com)

Add new test file from Ruby implementation.
Add new test file from Ruby implementation.
