Raise more semantic error for unsupported schemes

lib/httparty/exceptions.rb

@@ -1,7 +1,10 @@
 module HTTParty
   # Exception raised when you attempt to set a non-existant format
   class UnsupportedFormat < StandardError; end
-  
+
+  # Exception raised when using a URI scheme other than HTTP or HTTPS
+  class UnsupportedURIScheme < StandardError; end
+
   # Exception that is raised when request has redirected too many times
   class RedirectionTooDeep < StandardError; end
-end
+end

lib/httparty/request.rb

@@ -30,7 +30,7 @@ module HTTParty
       end
 
       unless SupportedURISchemes.include? new_uri.class
-        raise ArgumentError, "Cannot parse '#{new_uri}' as a supported URI class"
+        raise UnsupportedURIScheme, "'#{new_uri}' Must be HTTP or HTTPS"
       end
 
       new_uri

spec/httparty_spec.rb

@@ -352,20 +352,20 @@ describe HTTParty do
       stub_http_response_with('google.html')
       lambda do
         HTTParty.get('http://google.com')
-      end.should_not raise_error(ArgumentError)
+      end.should_not raise_error(HTTParty::UnsupportedURIScheme)
     end
 
     it "should accept https URIs" do
       stub_http_response_with('google.html')
       lambda do
         HTTParty.get('https://google.com')
-      end.should_not raise_error(ArgumentError)
+      end.should_not raise_error(HTTParty::UnsupportedURIScheme)
     end
 
     it "should raise an ArgumentError on URIs that are not http or https" do
       lambda do
         HTTParty.get("file:///there_is_no_party_on/my/filesystem")
-      end.should raise_error(ArgumentError)
+      end.should raise_error(HTTParty::UnsupportedURIScheme)
     end
 
     it "should raise an InvalidURIError on URIs that can't be parsed at all" do