Fix a syntax error that made agent.redirect_ok = :permanent not working.

Finally add a test for redirect_ok.

lib/mechanize/http/agent.rb

@@ -598,7 +598,7 @@ def response_redirect response, method, page, redirects
     when false, nil
       return page
     when :permanent
-      return page if response_class != Net::HTTPMovedPermanently
+      return page unless Net::HTTPMovedPermanently === response
     end
 
     log.info("follow redirect to: #{response['Location']}") if log

test/test_redirect_ok.rb

@@ -0,0 +1,25 @@
+require "helper"
+
+class TestRedirectOk < MiniTest::Unit::TestCase
+  def setup
+    @agent = Mechanize.new
+  end
+
+  def test_false
+    @agent.redirect_ok = false
+    page = @agent.get('http://localhost/redirect_ok')
+    assert_equal(URI('http://localhost/redirect_ok'), @agent.page.uri)
+  end
+
+  def test_true
+    @agent.redirect_ok = true
+    page = @agent.get('http://localhost/redirect_ok')
+    assert_equal(URI('http://localhost/redirect_ok?q=5'), @agent.page.uri)
+  end
+
+  def test_permanent
+    @agent.redirect_ok = :permanent
+    page = @agent.get('http://localhost/redirect_ok')
+    assert_equal(URI('http://localhost/redirect_ok?q=3'), @agent.page.uri)
+  end
+end