Add the ability to handle escaped HTML characters in trailing text

Add tests for unicode and escaped HTML characters

common/lib/capa/capa/inputtypes.py

@@ -457,8 +457,9 @@ class TextLine(InputTypeBase):
     """
     A text line input.  Can do math preview if "math"="1" is specified.
 
-    If "trailing_text" is set to a value, then the textline will be shown with the value after the text input. 
-    This is useful if you would like to specify a specific type of units for the text input.
+    If "trailing_text" is set to a value, then the textline will be shown with the value after the text input,
+    and before the checkmark or any input-specific feedback. HTML will not work, but properly escaped HTML characters will.
+    This feature is useful if you would like to specify a specific type of units for the text input.
 
     If the hidden attribute is specified, the textline is hidden and the input id is stored in a div with name equal
     to the value of the hidden attribute.  This is used e.g. for embedding simulations turned into questions.

common/lib/capa/capa/templates/textline.html

@@ -31,7 +31,7 @@
             style="display:none;"
         % endif
    />
-   ${trailing_text}
+   ${trailing_text | h}
 
       <p class="status">
         % if status == 'unsubmitted':

common/lib/capa/capa/tests/test_inputtypes.py

+# coding='utf-8'
 """
-Tests of input types.
+feature Tests of input types.
 
 TODO:
 - refactor: so much repetive code (have factory methods that build xml elements directly, etc)
@@ -20,6 +21,7 @@ import json
 from lxml import etree
 import unittest
 import xml.sax.saxutils as saxutils
+import unicodedata as ud
 
 from . import test_system
 from capa import inputtypes
@@ -219,7 +221,10 @@ class TextLineTest(unittest.TestCase):
     def test_trailing_text_rendering(self):
         size = "42"
         trailing_text = 'm/s'
-        xml_str = """<textline id="prob_1_2" size="{size}" trailing_text="{tt}"/>""".format(size=size, tt=trailing_text)
+        xml_str = """<textline id="prob_1_2" 
+                        size="{size}" 
+                        trailing_text="{tt}"
+                        />""".format(size=size, tt=trailing_text)
 
         element = etree.fromstring(xml_str)
 
@@ -241,6 +246,63 @@ class TextLineTest(unittest.TestCase):
         self.assertEqual(context, expected)
 
 
+    def test_trailing_unicode(self):
+        size = "42"
+        trailing_text = u'\xc3'
+        print trailing_text
+        xml_str = u"""<textline id="prob_1_2" 
+                         size="{size}" 
+                         trailing_text="{tt}"
+                         />""".format(size=size, tt=trailing_text)
+
+        element = etree.fromstring(xml_str)
+
+        state = {'value': 'BumbleBee', }
+        the_input = lookup_tag('textline')(test_system, element, state)
+
+        context = the_input._get_render_context()
+
+        expected = {'id': 'prob_1_2',
+                    'value': 'BumbleBee',
+                    'status': 'unanswered',
+                    'size': size,
+                    'msg': '',
+                    'hidden': False,
+                    'inline': False,
+                    'do_math': False,
+                    'trailing_text': trailing_text,
+                    'preprocessor': None}
+        self.assertEqual(context, expected)
+
+
+    def test_trailing_text_special_characters(self):
+        size = "42"
+        trailing_text = 'a &lt; b'
+        xml_str = """<textline id="prob_1_2" 
+                        size="{size}" 
+                        trailing_text="{tt}"
+                        />""".format(size=size, tt=trailing_text)
+
+        element = etree.fromstring(xml_str)
+
+        state = {'value': 'BumbleBee', }
+        the_input = lookup_tag('textline')(test_system, element, state)
+
+        context = the_input._get_render_context()
+
+        expected = {'id': 'prob_1_2',
+                    'value': 'BumbleBee',
+                    'status': 'unanswered',
+                    'size': size,
+                    'msg': '',
+                    'hidden': False,
+                    'inline': False,
+                    'do_math': False,
+                    'trailing_text': 'a < b',
+                    'preprocessor': None}
+        self.assertEqual(context, expected)
+
+
 class FileSubmissionTest(unittest.TestCase):
     '''
     Check that file submission inputs work