Handle json requests in show_error_notice

If the request is a accepts json we need to return
the error message as json.

app/controllers/alchemy/admin/base_controller.rb

@@ -48,14 +48,13 @@ def show_error_notice(error)
         @error = error
         # truncate the message, because very long error messages (i.e from mysql2) causes cookie overflow errors
         @notice = error.message[0..255]
-        @trace = error.backtrace[0..50]
-        if request.xhr?
+        if request.format.json?
+          render json: {message: @notice}, status: 500
+        elsif request.xhr?
           render action: "error_notice"
         else
-          respond_to do |format|
-            format.html { render "500", status: 500 }
-            format.json { render json: {message: @notice}, status: 500 }
-          end
+          @trace = error.backtrace[0..50]
+          render "500", status: 500
         end
       end
 

spec/controllers/alchemy/admin/base_controller_spec.rb

@@ -93,6 +93,63 @@
     end
   end
 
+  describe "#show_error_notice" do
+    let(:error) do
+      ActiveRecord::ActiveRecordError.new("Database is busy")
+    end
+
+    subject do
+      controller.send(:show_error_notice, error)
+    end
+
+    before do
+      allow(controller).to receive(:render)
+    end
+
+    context "for a json request" do
+      before do
+        expect(controller).to receive(:request) do
+          double(format: double(json?: true))
+        end
+      end
+
+      it "returns error message" do
+        subject
+        expect(controller).to have_received(:render).with(
+          json: {message: "Database is busy"},
+          status: 500
+        )
+      end
+    end
+
+    context "for a xhr request" do
+      before do
+        expect(controller).to receive(:request) do
+          double(xhr?: true, format: double(json?: false))
+        end.twice
+      end
+
+      it "renders error notice" do
+        subject
+        expect(controller).to have_received(:render).with(action: "error_notice")
+      end
+    end
+
+    context "for a html request" do
+      before do
+        expect(controller).to receive(:request) do
+          double(xhr?: false, format: double(json?: false))
+        end.twice
+        error.set_backtrace(%(foo))
+      end
+
+      it "renders error template" do
+        subject
+        expect(controller).to have_received(:render).with("500", status: 500)
+      end
+    end
+  end
+
   context "when current_alchemy_user is present" do
     let!(:page_1) { create(:alchemy_page, name: "Page 1") }
     let!(:page_2) { create(:alchemy_page, name: "Page 2") }