fix(docstring.feature): extend DocString.feature tests to cover failing scenario

DocString.feature will fail when ES6 template literals are present in the DocString.

Author: ralphpulselive

cypress/integration/DocString.feature

@@ -9,4 +9,13 @@ Feature: Being a plugin handling DocString scenario
     expect(true).to.equal(true)
     variableToVerify = "hello world"
     """
-    Then I ran it and verify that it executes it
+    Then I ran it and verify that it executes it
+
+  Scenario: DocString
+    When I use DocString for freemarker code like this
+    """
+    <div>
+      <h1>${ article.title }</h1>
+    </div>
+    """
+    Then I can interpret it as a string

cypress/support/step_definitions/docString.js

@@ -13,3 +13,12 @@ then("I ran it and verify that it executes it", () => {
   eval(code);
   expect(variableToVerify).to.equal("hello world");
 });
+
+let freemarkerSnippet = "";
+when("I use DocString for freemarker code like this", dataString => {
+  freemarkerSnippet = dataString;
+});
+
+then("I can interpret it as a string", () => {
+  expect(freemarkerSnippet).to.be.a("string");
+});