Data source attribute access and detection affordances

lib/set_attributes/data_source/hash.rb

@@ -11,8 +11,13 @@ def self.verify_mapping(source, include)
         return include
       end
 
-      def get_value(source_attribute)
-        source[source_attribute]
+      def get_value(attribute)
+        source[attribute]
+      end
+      alias :[] :get_value
+
+      def attribute?(attribute)
+        source.keys.include?(attribute)
       end
     end
   end

lib/set_attributes/data_source/object.rb

@@ -13,9 +13,14 @@ def self.verify_mapping(source, include)
         return include
       end
 
-      def get_value(source_attribute)
-        return nil unless source.respond_to?(source_attribute)
-        source.send(source_attribute)
+      def get_value(attribute)
+        return nil unless attribute?(attribute)
+        source.send(attribute)
+      end
+      alias :[] :get_value
+
+      def attribute?(attribute)
+        source.respond_to?(attribute)
       end
     end
   end

test/automated/data_source/attribute_predicate.rb

@@ -0,0 +1,32 @@
+require_relative '../../test_init'
+
+context "Data Source" do
+  context "Attribute Predicate" do
+    hash_source = Controls::Hash.example
+    object_source = Controls::Object.example
+
+    [[hash_source, 'Hash'], [object_source, 'Object']].each do |source_info|
+
+      source = source_info[0]
+      source_type = source_info[1]
+
+      context "#{source_type} Source" do
+        data_source = SetAttributes::DataSource.build_data_source(source)
+
+        value = data_source.get_value(:some_attribute)
+
+        context "Attribute Present in the Source" do
+          test "Detected" do
+            assert(data_source.attribute?(:some_attribute))
+          end
+        end
+
+        context "Attribute Not Present in the Source" do
+          test "Not Detected" do
+            refute(data_source.attribute?(Controls::Attribute::Random.example))
+          end
+        end
+      end
+    end
+  end
+end

test/automated/set_attributes/missing_source_attribute.rb

@@ -14,9 +14,9 @@
 
       data_source = SetAttributes::DataSource.build_data_source(source)
 
-      refute(data_source.get_value(:some_attribute).nil?)
-      refute(data_source.get_value(:some_other_attribute).nil?)
-      assert(data_source.get_value(:yet_another_attribute).nil?)
+      refute(data_source[:some_attribute].nil?)
+      refute(data_source[:some_other_attribute].nil?)
+      assert(data_source[:yet_another_attribute].nil?)
 
       context "#{source_type} Source" do
         receiver = Controls::Object::New.example

test/automated/set_attributes/transform.rb

@@ -17,9 +17,9 @@
 
       data_source = SetAttributes::DataSource.build_data_source(source)
 
-      refute(data_source.get_value(:an_attribute).nil?)
-      refute(data_source.get_value(:some_other_attribute).nil?)
-      assert(data_source.get_value(:yet_another_attribute).nil?)
+      refute(data_source[:an_attribute].nil?)
+      refute(data_source[:some_other_attribute].nil?)
+      assert(data_source[:yet_another_attribute].nil?)
 
       context "#{source_type} Source" do
         receiver = Controls::Object::New.example