Você pode executar um determinado teste passando para tconsole o número dele:
tconsole> all
Running tests...
Web::Posts::CommentsControllerTest 1
P test_should_create_comment 0.482066s 1-1
P test_should_destroy_comment 0.108127s 1-2
Finished tests in 0.611542s, 3.2704 tests/s, 3.2704 assertions/s.
2 tests, 2 assertions, 2 passes, 0 failures, 0 errors, 0 skips
tconsole> 1-1
Running tests...
Web::Posts::CommentsControllerTest 1
P test_should_create_comment 0.435173s 1-1
Finished tests in 0.495979s, 2.0162 tests/s, 2.0162 assertions/s.
1 tests, 1 assertions, 1 passes, 0 failures, 0 errors, 0 skips