Fix RegexpFilter, notably used for mspec run -p/-P and test it

* Avoid inheritance, it just makes things more complex.

lib/mspec/runner/filters/regexp.rb

@@ -1,7 +1,23 @@
-require 'mspec/runner/filters/match'
+class RegexpFilter
+  def initialize(what, *regexps)
+    @what = what
+    @regexps = to_regexp(*regexps)
+  end
+
+  def ===(string)
+    @regexps.any? { |regexp| regexp === string }
+  end
+
+  def register
+    MSpec.register @what, self
+  end
+
+  def unregister
+    MSpec.unregister @what, self
+  end
 
-class RegexpFilter < MatchFilter
-  def to_regexp(*strings)
-    strings.map { |str| Regexp.new str }
+  def to_regexp(*regexps)
+    regexps.map { |str| Regexp.new str }
   end
+  private :to_regexp
 end

spec/runner/filters/regexp_spec.rb

@@ -2,12 +2,30 @@
 require 'mspec/runner/mspec'
 require 'mspec/runner/filters/regexp'
 
+describe MatchFilter, "#===" do
+  before :each do
+    @filter = RegexpFilter.new nil, 'a(b|c)', 'b[^ab]', 'cc?'
+  end
+
+  it "returns true if the argument matches any of the #initialize strings" do
+    @filter.===('ab').should == true
+    @filter.===('bc suffix').should == true
+    @filter.===('prefix cc').should == true
+  end
+
+  it "returns false if the argument matches none of the #initialize strings" do
+    @filter.===('aa').should == false
+    @filter.===('ba').should == false
+    @filter.===('prefix d suffix').should == false
+  end
+end
+
 describe RegexpFilter, "#to_regexp" do
   before :each do
     @filter = RegexpFilter.new nil
   end
 
   it "converts its arguments to Regexp instances" do
-    @filter.to_regexp('a(b|c)', 'b[^ab]', 'cc?').should == [/a(b|c)/, /b[^ab]/, /cc?/]
+    @filter.send(:to_regexp, 'a(b|c)', 'b[^ab]', 'cc?').should == [/a(b|c)/, /b[^ab]/, /cc?/]
   end
 end