Construct subsets of your tests

    TestSubset::Task.new("foo") do |test|
      test.units "foo/*"
      test.functionals "foo/*", "bar/*", "*{foo,bar}*"
      test.integration "foo/*"
    end

Execute them like so

    rake test:foo:units       # just units
    rake test:foo:functionals # just functionals
    rake test:foo:integration # just integration
    rake test:foo             # all

And some additional tasks

    rake test:foo:units_and_functionals
    rake test:foo:functionals_and_units

    rake test:foo:units_and_integration
    rake test:foo:integration_and_units

    rake test:foo:functionals_and_integration
    rake test:foo:integration_and_functionals