refactor initializing parameters check

Author: Jay Parekh

lib/imagekit/imagekit.rb

@@ -16,13 +16,15 @@ class ImageKitClient
     attr_reader :file
 
     def initialize(private_key, public_key, url_endpoint, transformation_pos = nil, options = nil)
-      
-      unless(private_key.is_a?(String) && public_key.is_a?(String) && url_endpoint.is_a?(String))
-        raise ArgumentError, "ImageKit Parameters should be valid string"
+
+      unless(private_key.is_a?(String) && private_key.to_s.strip.length != 0)
+        raise ArgumentError, "ImageKit private key must be a valid, non-blank string"
+      end
+      unless(public_key.is_a?(String) && public_key.to_s.strip.length != 0)
+        raise ArgumentError, "ImageKit public key must be a valid, non-blank string"
       end
-      
-      unless(private_key.to_s.strip.length != 0 && public_key.to_s.strip.length != 0 && url_endpoint.to_s.strip.length != 0)
-        raise ArgumentError, "ImageKit Parameters cannot be blank"
+      unless(url_endpoint.is_a?(String) && url_endpoint.to_s.strip.length != 0)
+        raise ArgumentError, "ImageKit URL Endpoint should be valid, non-blank string"
       end
 
       @private_key = private_key