Move toXML code into edit.coffee, create unit test scaffolding.

common/lib/xmodule/xmodule/js/spec/problem/edit_spec.coffee

+describe 'MarkdownEditingDescriptor', ->
+  describe 'markdownToXml', ->
+    it 'converts raw text to paragraph', ->
+      data = MarkdownEditingDescriptor.markdownToXml('foo')
+      expect(data).toEqual('<p>foo</p>')
\ No newline at end of file

common/lib/xmodule/xmodule/js/src/problem/edit.coffee

@@ -17,7 +17,7 @@ class @MarkdownEditingDescriptor extends XModule.Descriptor
       })
       @setCurrentEditor(@markdown_editor)
 
-  onMarkdownEditorUpdate:  ->
+  onMarkdownEditorUpdate: ->
     console.log('update')
     @updateXML()
 
@@ -32,7 +32,7 @@ class @MarkdownEditingDescriptor extends XModule.Descriptor
       #    onMarkdownEditorUpdate();
     else
       @setCurrentEditor(@xml_editor)
-      #    xmlEditor.refresh();
+  #    xmlEditor.refresh();
 
   setCurrentEditor: (editor) ->
     $(@current_editor.getWrapperElement()).hide()
@@ -43,3 +43,108 @@ class @MarkdownEditingDescriptor extends XModule.Descriptor
   save: ->
     $body.off('click', '.editor-tabs .tab', @changeEditor)
     data: @xml_editor.getValue()
+
+  @markdownToXml: (markdown)->
+    toXml = `function(markdown) {
+      var xml = markdown;
+
+      // replace headers
+      xml = xml.replace(/(^.*?$)(?=\n\=\=+$)/gm, '<h1>$1</h1>');
+      xml = xml.replace(/\n^\=\=+$/gm, '');
+
+      // group multiple choice answers
+      xml = xml.replace(/(^\s*\(.?\).*?$\n*)+/gm, function(match, p) {
+        var groupString = '<multiplechoiceresponse>\n';
+        groupString += '  <choicegroup type="MultipleChoice">\n';
+        var options = match.split('\n');
+        for(var i = 0; i < options.length; i++) {
+          if(options[i].length > 0) {
+            var value = options[i].split(/^\s*\(.?\)\s*/)[1];
+            var correct = /^\s*\(x\)/i.test(options[i]);
+            groupString += '    <choice correct="' + correct + '">' + value + '</choice>\n';
+          }
+        }
+        groupString += '  </choicegroup>\n';
+        groupString += '</multiplechoiceresponse>\n\n';
+        return groupString;
+      });
+
+      // group check answers
+      xml = xml.replace(/(^\s*\[.?\].*?$\n*)+/gm, function(match, p) {
+        var groupString = '<multiplechoiceresponse>\n';
+        groupString += '  <choicegroup type="MultipleChoiceChecks">\n';
+        var options = match.split('\n');
+        for(var i = 0; i < options.length; i++) {
+          if(options[i].length > 0) {
+            var value = options[i].split(/^\s*\[.?\]\s*/)[1];
+            var correct = /^\s*\[x\]/i.test(options[i]);
+            groupString += '    <choice correct="' + correct + '">' + value + '</choice>\n';
+          }
+        }
+        groupString += '  </choicegroup>\n';
+        groupString += '</multiplechoiceresponse>\n\n';
+        return groupString;
+      });
+
+      // replace videos
+      xml = xml.replace(/\{\{video\s(.*?)\}\}/g, '<video youtube="1.0:$1" />\n\n');
+
+      // replace string and numerical
+      xml = xml.replace(/^\=\s*(.*?$)/gm, function(match, p) {
+        var string;
+        var params = /(.*?)\+\-\s*(.*?)/.exec(p);
+        if(parseFloat(p)) {
+          if(params) {
+            string = '<numericalresponse answer="' + params[1] + '">\n';
+            string += '  <responseparam type="tolerance" default="' + params[2] + '" />\n';
+          } else {
+            string = '<numericalresponse answer="' + p + '">\n';
+          }
+          string += '  <textline />\n';
+          string += '</numericalresponse>\n\n';
+        } else {
+          string = '<stringresponse answer="' + p + '" type="ci">\n  <textline size="20"/>\n</stringresponse>\n\n';
+        }
+        return string;
+      });
+
+      // replace selects
+      xml = xml.replace(/\[\[(.+?)\]\]/g, function(match, p) {
+        var selectString = '\n<optionresponse>\n';
+        selectString += '  <optioninput options="(';
+        var options = p.split(/\,\s*/g);
+        for(var i = 0; i < options.length; i++) {
+          selectString += "'" + options[i].replace(/\((.*?)\)/g, '$1') + "'" + (i < options.length -1 ? ',' : '');
+        }
+        selectString += ')" correct="';
+        var correct = /\((.*?)\)/g.exec(p);
+        if (correct) selectString += correct[1];
+        selectString += '"></optioninput>\n';
+        selectString += '</optionresponse>\n\n';
+        return selectString;
+      });
+
+      // split scripts and wrap paragraphs
+      var splits = xml.split(/(\<\/?script.*?\>)/g);
+      var scriptFlag = false;
+      for(var i = 0; i < splits.length; i++) {
+        if(/\<script/.test(splits[i])) {
+          scriptFlag = true;
+        }
+        if(!scriptFlag) {
+          splits[i] = splits[i].replace(/(^(?!\s*\<|$).*$)/gm, '<p>$1</p>');
+        }
+        if(/\<\/script/.test(splits[i])) {
+          scriptFlag = false;
+        }
+      }
+      xml = splits.join('');
+
+      // rid white space
+      xml = xml.replace(/\n\n\n/g, '\n');
+
+      return xml;
+    }
+    `
+    return toXml markdown
+