Using require_relative to help using minitest

[fabioperrella]

Hi!

When I was doing #66 I was trying to find a way to run only 1 test scenario, like I am used to do with rspec.

Then, installed the gem m, tried to run only 1 scenario and got this error:

$ m tests/jpeg_test.rb:36
Failed loading test file:
cannot load such file -- test_helper
There were no tests found.

Then, I changed require by require_relative and I managed to run the way I wanted:

$ m tests/jpeg_test.rb:36
Run options: -n "/^(test_size)$/" --seed 40264

# Running:

.

Finished in 0.001608s, 621.8906 runs/s, 3731.3435 assertions/s.
1 runs, 6 assertions, 0 failures, 0 errors, 0 skips

I'm not sure if there is a way to run a specific scenario with the gem test-unit which is the default for this project.

But I think the modification that I'm proposing will not affect anything.

[remvee]

This breaks Ruby 1.8.7 support (see https://github.com/remvee/exifr/blob/master/exifr.gemspec#L10). Also running a single test is possible without any extra gems; ruby -I tests tests/jpeg_test.rb -n test_size

[fabioperrella]

humm, I didn't notice that, tks!