'Preview in Latex' was not working in ORA.

TNL-1755

openassessment/xblock/static/js/src/lms/oa_response.js

@@ -96,7 +96,7 @@ OpenAssessment.ResponseView.prototype = {
             function(eventObject) {
                 eventObject.preventDefault();
                 // extract typed-in response and replace newline with br
-                var preview_text = sel.find('#submission__answer__value').val();
+                var preview_text = sel.find('.submission__answer__part__text__value').val();
                 var preview_container = sel.find('#preview_content');
                 preview_container.html(preview_text.replace(/\r\n|\r|\n/g,"<br />"));
 

test/acceptance/pages.py

@@ -71,10 +71,36 @@ class SubmissionPage(OpenAssessmentPage):
             BrokenPromise: The response was not submitted successfully.
 
         """
-        self.q(css="textarea#submission__answer__value").fill(response_text)
+        self.wait_for_element_visibility("textarea.submission__answer__part__text__value", "Textarea is present")
+        self.q(css="textarea.submission__answer__part__text__value").fill(response_text)
         self.submit()
         EmptyPromise(lambda: self.has_submitted, 'Response is completed').fulfill()
 
+    def fill_latex(self, latex_query):
+        """
+        Fill the latex expression
+        Args:
+         latex_query (unicode): Latex expression text
+        """
+        self.wait_for_element_visibility("textarea.submission__answer__part__text__value", "Textarea is present")
+        self.q(css="textarea.submission__answer__part__text__value").fill(latex_query)
+
+    def preview_latex(self):
+        # Click 'Preview in Latex' button on the page.
+        self.q(css="button#submission__preview").click()
+        self.wait_for_element_visibility("#preview_content .MathJax", "Verify Preview Latex expression")
+
+    @property
+    def latex_preview_button_is_disabled(self):
+        """
+        Check if 'Preview in Latex' button is disabled
+
+        Returns:
+            bool
+        """
+        preview_latex_button_class = self.q(css="button#submission__preview").attrs('class')
+        return 'is--disabled' in preview_latex_button_class
+
     @property
     def has_submitted(self):
         """

test/acceptance/tests.py

@@ -55,6 +55,7 @@ class OpenAssessmentTest(WebAppTest):
     }
 
     SUBMISSION = u"This is a test submission."
+    LATEX_SUBMISSION = u"[mathjaxinline]( \int_{0}^{1}xdx \)[/mathjaxinline]"
     OPTIONS_SELECTED = [1, 2]
     EXPECTED_SCORE = 6
 
@@ -106,6 +107,20 @@ class SelfAssessmentTest(OpenAssessmentTest):
         # Check browser scrolled back to top
         self.assertTrue(self.self_asmnt_page.is_on_top)
 
+    @retry()
+    @attr('acceptance')
+    def test_latex(self):
+        self.auto_auth_page.visit()
+        # 'Preview in Latex' button should be disabled at the page load
+        self.assertTrue(self.submission_page.latex_preview_button_is_disabled)
+
+        # Fill latex expression, & Verify if 'Preview in Latex is enabled'
+        self.submission_page.visit().fill_latex(self.LATEX_SUBMISSION)
+        self.assertFalse(self.submission_page.latex_preview_button_is_disabled)
+
+        # Click 'Preview in Latex' button & Verify if it was rendered
+        self.submission_page.preview_latex()
+
 
 class PeerAssessmentTest(OpenAssessmentTest):
     """