Allow to run tests on an entire tree of directories

* Set up `-r` and `--recursive` options in Parser
* Add more nested subdirectories under examples/subdir/ to use in
  EverythingTest#test_running_tests_recursively.
* Update README.md with an example of -r usage

Author: davidcpell

README.md

@@ -114,6 +114,18 @@ Want to run the whole test? Just leave off the line number.
 
     1 tests, 2 assertions, 0 failures, 0 errors, 0 skips
 
+If you want to run all the tests in a directory as well as its subdirectories, use the `-r` flag: 
+
+    $ m -r test/models
+    "Searching provided directory for tests recursively"
+    Run options: 
+
+    ..
+
+    Finished in 3.459902s, 45.0880 runs/s, 87.5747 assertions/s.
+
+    156 tests, 303 assertions, 0 failures, 0 errors, 13 skips
+
 
 SUPPORT
 =======

lib/m/parser.rb

@@ -25,7 +25,7 @@ def parse
           Rake::TestTask.new(:m_custom) do |t|
             t.libs << 'test'
             t.libs << 'spec'
-            t.test_files = FileList["#{testable.file}/*test*.rb", "#{testable.file}/*spec*.rb"]
+            t.test_files = FileList[wildcard("test"), wildcard("spec")]
           end
           # Invoke the rake task and exit, hopefully it'll work!
           begin
@@ -67,8 +67,21 @@ def parse_options!(argv)
           testable.line = line
         end
 
+        opts.on '-r', '--recursive DIR', 'Search provided directory recursively.' do |directory|
+          testable.recursive = true
+          argv << directory
+        end
+
         opts.parse! argv
       end
     end
+
+    def wildcard(type)
+      if testable.recursive
+        "#{testable.file}/**/*#{type}*.rb"
+      else
+        "#{testable.file}/*#{type}*.rb"
+      end
+    end
   end
 end

lib/m/testable.rb

@@ -1,11 +1,12 @@
 module M
   class Testable
-    attr_accessor :file
+    attr_accessor :file, :recursive
     attr_reader :line
 
-    def initialize(file = "", line = nil)
+    def initialize(file = "", line = nil, recursive = false)
       @file = file
       @line = line
+      @recursive = recursive
     end
 
     def line=(line)

test/examples/subdir/another_subdir/d_test.rb

@@ -0,0 +1,7 @@
+require_relative '../../../test_helper'
+
+class DTest < MTest
+  def test_d
+    assert_equal 1, 1
+  end
+end

test/examples/subdir/another_subdir/yet_another_subdir/e_test.rb

@@ -0,0 +1,7 @@
+require_relative '../../../../test_helper'
+
+class ETest < MTest
+  def test_e
+    assert_equal 1, 1
+  end
+end

test/options_test.rb

@@ -30,4 +30,14 @@ def test_line_option_has_precedence_over_colon_format
     output = m('--line 20 examples/minitest_4_example_test.rb:2')
     assert_output(/1 tests, 1 assertions/, output)
   end
+
+  def test_recursive_option
+    output = m('-r examples/subdir')
+    assert_output(/5 tests/, output)
+  end
+
+  def test_recursive_option_without_directory_arg_fails
+    output = m('-r')
+    assert_match(/OptionParser::MissingArgument/, output)
+  end
 end