Add missing attributes/fields from unit tests for Sample Metadata

spec/resources/api/v2/sample_metadata_resource_spec.rb

@@ -10,21 +10,27 @@
 
   # Test attributes
   it 'has the expected attributes', :aggregate_failures do
-    expect(resource).to have_attribute :sample_common_name
-    expect(resource).to have_attribute :supplier_name
+    expect(resource).to have_attribute :cohort
     expect(resource).to have_attribute :collected_by
-    expect(resource).to have_attribute :donor_id
     expect(resource).to have_attribute :concentration
+    expect(resource).to have_attribute :donor_id
+    expect(resource).to have_attribute :gender
+    expect(resource).to have_attribute :sample_common_name
+    expect(resource).to have_attribute :sample_description
+    expect(resource).to have_attribute :supplier_name
     expect(resource).to have_attribute :volume
   end
 
   # Updatable fields
   it 'allows updating of read-write fields', :aggregate_failures do
-    expect(resource).to have_updatable_field :sample_common_name
-    expect(resource).to have_updatable_field :supplier_name
+    expect(resource).to have_updatable_field :cohort
     expect(resource).to have_updatable_field :collected_by
-    expect(resource).to have_updatable_field :donor_id
     expect(resource).to have_updatable_field :concentration
+    expect(resource).to have_updatable_field :donor_id
+    expect(resource).to have_updatable_field :gender
+    expect(resource).to have_updatable_field :sample_common_name
+    expect(resource).to have_updatable_field :sample_description
+    expect(resource).to have_updatable_field :supplier_name
     expect(resource).to have_updatable_field :volume
   end