Fix handling of errors in cypress tests

client/cypress/support/commands.ts

@@ -161,16 +161,14 @@ Cypress.Commands.add('mockGraphql', (options?: any) => {
         rootValue.constructor === GraphQLError ||
         rootValue.constructor.name === "GraphQLError"
       ) {
-        return Promise.resolve()
-          .then(
-            () =>
-              new Response(
-                JSON.stringify({
-                  data: {},
-                  errors: [rootValue]
-                })
-              )
-          );
+        return req.reply(
+          {
+            body: {
+              data: {},
+              errors: [rootValue]
+            }
+          }
+        );
       }
 
       graphql({