Merge pull request #313 from DFE-Digital/improve-error-presenter-test…

…ing-and-setup Improve the setup of error presenters
x-govuk · Sep 1, 2021 · c9add91 · c9add91
2 parents 40e319c + 02965ff
commit c9add91
Show file tree

Hide file tree

Showing 2 changed files with 18 additions and 12 deletions.
diff --git a/lib/govuk_design_system_formbuilder/elements/error_summary.rb b/lib/govuk_design_system_formbuilder/elements/error_summary.rb
@@ -42,13 +42,10 @@ def list
       # error_messages from our object. Otherwise (if it's any other object),
       # treat it like a presenter
       def presenter
-        return @presenter.new(error_messages) if @presenter.is_a?(Class)
-
-        unless @presenter.respond_to?(:formatted_error_messages)
-          fail(ArgumentError, "error summary presenter doesn't implement #formatted_error_messages")
+        (@presenter.is_a?(Class) ? @presenter.new(error_messages) : @presenter).tap do |p|
+          fail(ArgumentError, "error summary presenter doesn't implement #formatted_error_messages") unless
+            p.respond_to?(:formatted_error_messages)
         end
-
-        @presenter
       end
 
       def error_messages

diff --git a/spec/govuk_design_system_formbuilder/builder/error_summary_spec.rb b/spec/govuk_design_system_formbuilder/builder/error_summary_spec.rb
@@ -472,6 +472,15 @@ def formatted_error_messages
             end
           end
         end
+
+        context "when the custom presenter is a class that doesn't implement #formatted_error_messages" do
+          let(:non_presenter) { OpenStruct }
+          subject { builder.send(*args, presenter: non_presenter) }
+
+          specify "fails with an appropriate error message" do
+            expect { subject }.to raise_error(ArgumentError, "error summary presenter doesn't implement #formatted_error_messages")
+          end
+        end
       end
 
       context "as an instance" do
@@ -484,14 +493,14 @@ def formatted_error_messages
             end
           end
         end
-      end
 
-      context "when the custom presenter doesn't implement #formatted_error_messages" do
-        let(:non_presenter) { "totally not a presenter" }
-        subject { builder.send(*args, presenter: non_presenter) }
+        context "when the custom presenter is an instance that doesn't implement #formatted_error_messages" do
+          let(:non_presenter) { "totally not a presenter" }
+          subject { builder.send(*args, presenter: non_presenter) }
 
-        specify "fails with an appropriate error message" do
-          expect { subject }.to raise_error(ArgumentError, "error summary presenter doesn't implement #formatted_error_messages")
+          specify "fails with an appropriate error message" do
+            expect { subject }.to raise_error(ArgumentError, "error summary presenter doesn't implement #formatted_error_messages")
+          end
         end
       end
     end