Add :via option which overrides the default transport mechanism

lib/pony.rb

@@ -5,7 +5,16 @@
 module Pony
 	def self.mail(options)
 		raise(ArgumentError, ":to is required") unless options[:to]
-		transport build_tmail(options)
+
+	  unless(via = options[:via].to_s).empty?
+	    if via == 'smtp' || via == 'sendmail'
+	      send("transport_via_#{via}", build_tmail(options))
+      else
+        raise(ArgumentError, ":via must be either smtp or sendmail")
+      end
+    else
+	    transport build_tmail(options)
+    end
 	end
 
 	def self.build_tmail(options)

spec/pony_spec.rb

@@ -72,4 +72,21 @@
 			Pony.transport_via_smtp(mock('tmail', :to => 'to', :from => 'from', :to_s => 'message'))
 		end
 	end
+
+  describe ":via option should over-ride the default transport mechanism" do
+    it "should send via sendmail if :via => sendmail" do
+      Pony.should_receive(:transport_via_sendmail)
+  		Pony.mail(:to => 'joe@example.com', :via => :sendmail)
+		end
+
+    it "should send via smtp if :via => smtp" do
+      Pony.should_receive(:transport_via_smtp)
+  		Pony.mail(:to => 'joe@example.com', :via => :smtp)
+		end
+
+		it "should raise an error if via is neither smtp nor sendmail" do
+		  lambda { Pony.mail(:to => 'joe@plumber.com', :via => :pigeon) }.should raise_error(ArgumentError)
+	  end
+	end
+
 end