Be able to run metrics on a single file

[bf4]

Given a directory full of ruby files

When a single file is specified

Then MetricFu will run all configured metrics on that file

And output a report for that one file, graphs optional

Bonuses

• create a new AnalyzedFile object that takes in a filename and
  contains the results of all metrics run against it. (This is distinct from, but similar to, the notion of a MetricFile that represents a marshaled metric_fu report.
• use an MD5Tracker to only run metrics on changed files.

Suggested interface

analyzed_file = MetricFu::AnalyzedFile.new(filename)
analyzed_file.analyze! # runs metrics on the filename
analyzed_file.analysis # a hash of results from the above, compatible with the data in the report

This would likely require refactoring of the Generator and Hotspot classes

[MGotink]

What did you have in mind for running MetricFu against a single file? Some metrics don't support that. Run against the whole directory and filter out the results for that file?

[bf4]

I think that's a valid interpretation

[bf4]

This feature would allow, e.g. running metric_fu over code in a pre-commit hook