Raise ValidationError if properties are missing

lib/diaspora_federation/entity.rb

@@ -153,7 +153,7 @@ module DiasporaFederation
 
     def validate_missing_props(entity_data)
       missing_props = self.class.missing_props(entity_data)
-      raise ArgumentError, "missing required properties: #{missing_props.join(', ')}" unless missing_props.empty?
+      raise ValidationError, "missing required properties: #{missing_props.join(', ')}" unless missing_props.empty?
     end
 
     def setable?(name, val)

spec/lib/diaspora_federation/entity_spec.rb

@@ -15,7 +15,7 @@ module DiasporaFederation
       it "checks for required properties" do
         expect {
           Entities::TestDefaultEntity.new({})
-        }.to raise_error ArgumentError, "missing required properties: test1, test2"
+        }.to raise_error Entity::ValidationError, "missing required properties: test1, test2"
       end
 
       context "defaults" do

spec/support/shared_entity_specs.rb

@@ -12,7 +12,7 @@ shared_examples "an Entity subclass" do
 
     describe "initialize" do
       it "must not create blank instances" do
-        expect { described_class.new({}) }.to raise_error ArgumentError
+        expect { described_class.new({}) }.to raise_error DiasporaFederation::Entity::ValidationError
       end
 
       it "fails if nil was given" do