diff --git a/lib/rack/rewrite/rule.rb b/lib/rack/rewrite/rule.rb
index f992089..ded0c3d 100644
--- a/lib/rack/rewrite/rule.rb
+++ b/lib/rack/rewrite/rule.rb
@@ -226,7 +226,7 @@ def match(path)
 
         def string_matches?(string, matcher)
           if self.is_a_regexp?(matcher)
-            string =~ matcher
+            (string =~ matcher) != nil
           elsif matcher.is_a?(String)
             string == matcher
           elsif matcher.is_a?(Symbol)
diff --git a/test/rule_test.rb b/test/rule_test.rb
index d950c88..c9caf05 100644
--- a/test/rule_test.rb
+++ b/test/rule_test.rb
@@ -1,6 +1,6 @@
 require 'test_helper'
 
-class RuleTest < Test::Unit::TestCase
+class RuleTest < ZeroTest
 
   TEST_ROOT = File.dirname(__FILE__)
 
diff --git a/test/test_helper.rb b/test/test_helper.rb
index a11fd42..8509755 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -15,4 +15,17 @@ def rack_env_for(url, options = {})
 
 def supported_status_codes
   [:r301, :r302, :r303, :r307]
-end
\ No newline at end of file
+end
+
+class ZeroTest < Test::Unit::TestCase
+  def assert(test, msg= nil)
+    if test.class == Fixnum && test.zero?
+      super(false)
+    end
+    if msg.nil?
+      super(test)
+    else
+      super(test, msg)
+    end
+  end
+end