fix: don't wrap HTML data with newlines when serializing for LC

Closes: openedx#35525
kdmccormick · Sep 24, 2024 · 639b45f · 639b45f
1 parent 75d111a
commit 639b45f
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Showing 3 changed files with 87 additions and 7 deletions.
diff --git a/openedx/core/djangoapps/content_libraries/tests/test_runtime.py b/openedx/core/djangoapps/content_libraries/tests/test_runtime.py
@@ -3,6 +3,7 @@
 """
 import json
 from gettext import GNUTranslations
+from django.test import TestCase
 
 from completion.test_utils import CompletionWaffleTestMixin
 from django.db import connections, transaction
@@ -24,6 +25,7 @@
 from openedx.core.djangoapps.dark_lang.models import DarkLangConfig
 from openedx.core.djangoapps.xblock import api as xblock_api
 from openedx.core.djangolib.testing.utils import skip_unless_lms, skip_unless_cms
+from openedx.core.lib.xblock_serializer import api as serializer_api
 from common.djangoapps.student.tests.factories import UserFactory
 
 
@@ -59,6 +61,85 @@ def setUp(self):
             )
 
 
+@skip_unless_cms
+class ContentLibraryOlxTests(ContentLibraryContentTestMixin, TestCase):
+    """
+    Basic tests of the Learning-Core-based XBlock serialization-deserializatin using XBlocks in a content library.
+    """
+
+    def test_round_trip(self):
+        """
+        Test that if we deserialized and serialize a block repeatedly, two things hold true:
+
+        1. Even if the OLX changes format, the inner content does not change format.
+        2. The OLX settles into a stable state after 1 round trip.
+        """
+        # Let's use HTML, since it's easy, but the general concept here should apply to other blocks.
+        usage_key = library_api.create_library_block(self.library.key, "html", "roundtrip").usage_key
+
+        # The block's actual content (HTML in this case) has some extraneous spaces and newlines, as well as comment.
+        # We expect this to be preserved through the round-trips.
+        block_content = '''\
+<div class="double quot attr">
+    <div class='single quot attr'>
+        <p> There is a space on either side of this sentence. </p>
+        <p>\tThere is a tab on either side of this sentence.\t<p>
+        <p>🙃There is an emoji on either side of this sentence.🙂</p>
+        <p>There is nothing on either side of this sentence.</p>
+    </div>
+    <p><![CDATA[ This is an inner CDATA 🤯 Technically illegal in HTML, but let's test it anyway. ?!&<>\t ]]&gt;</p>
+    <!-- This is a comment within the HTML. -->
+</div>'''
+
+        # Outside the block content, our original OLX has some extraneous spaces and newlines, as well as a comment.
+        olx_1 = f'''\
+
+            <html
+                display_name="Round Trip Test HTML Block"
+                some_fake_attribute="some fake value"
+            ><![CDATA[{block_content}]]><!--
+                I am an OLX comment.
+            --></html>
+        '''
+
+        # Here is what we expect the OLX to settle down to. Notable changes:
+        #  * The url_name is added.
+        #  * The fake field is gone.
+        #  * The OLX comment is gone.
+        #  * A trailing newline is added at the end of the export.
+        # DEVS: If you are purposefully tweaking the formatting of the xblock serializer, then it's fine to
+        # update the value of this variable, as long as:
+        #  1. the {block_content} remains unchanged, and
+        #  2. the canonical_olx remains stable through the 2nd round trip.
+        canonical_olx = f'''\
+<html url_name="roundtrip" display_name="Round Trip Test HTML Block"><![CDATA[{block_content}]]></html>
+'''
+
+        # Save the block to LC, and re-load it.
+        library_api.set_library_block_olx(usage_key, olx_1)
+        library_api.publish_changes(self.library.key)
+        block_saved_1 = xblock_api.load_block(usage_key, self.staff_user)
+
+        # Content should be preserved...
+        assert block_saved_1.data == block_content
+
+        # ...but the serialized OLX will have changed to match the 'canonical' OLX.
+        olx_2 = serializer_api.serialize_xblock_to_olx(block_saved_1).olx_str
+        assert olx_2 == canonical_olx
+
+        # Now, save that OLX back to LC, and re-load it again.
+        library_api.set_library_block_olx(usage_key, olx_2)
+        library_api.publish_changes(self.library.key)
+        block_saved_2 = xblock_api.load_block(usage_key, self.staff_user)
+
+        # Content should be preserved...
+        assert block_saved_2.data == block_content
+
+        # ...and this time, the OLX should have settled too.
+        olx_3 = serializer_api.serialize_xblock_to_olx(block_saved_2).olx_str
+        assert olx_3 == canonical_olx
+
+
 class ContentLibraryRuntimeTests(ContentLibraryContentTestMixin):
     """
     Basic tests of the Learning-Core-based XBlock runtime using XBlocks in a

diff --git a/openedx/core/djangoapps/content_staging/tests/test_clipboard.py b/openedx/core/djangoapps/content_staging/tests/test_clipboard.py
@@ -1,7 +1,6 @@
 """
 Tests for the clipboard functionality
 """
-from textwrap import dedent
 from xml.etree import ElementTree
 
 from rest_framework.test import APIClient
@@ -155,11 +154,11 @@ def test_copy_html(self):
         assert olx_response.get("Content-Type") == "application/vnd.openedx.xblock.v1.html+xml"
         # For HTML, we really want to be sure that the OLX is serialized in this exact format (using CDATA), so we check
         # the actual string directly rather than using assertXmlEqual():
-        assert olx_response.content.decode() == dedent("""
-            <html url_name="toyhtml" display_name="Text"><![CDATA[
-            <a href='/static/handouts/sample_handout.txt'>Sample</a>
-            ]]></html>
-        """).lstrip()
+        assert olx_response.content.decode() == (
+            "<html url_name=\"toyhtml\" display_name=\"Text\"><![CDATA["
+            "<a href='/static/handouts/sample_handout.txt'>Sample</a>"
+            "]]></html>\n"
+        )
 
         # Now if we GET the clipboard again, the GET response should exactly equal the last POST response:
         assert client.get(CLIPBOARD_ENDPOINT).json() == response_data

diff --git a/openedx/core/lib/xblock_serializer/block_serializer.py b/openedx/core/lib/xblock_serializer/block_serializer.py
@@ -133,7 +133,7 @@ def _serialize_html_block(self, block) -> etree.Element:
 
         # Escape any CDATA special chars
         escaped_block_data = block.data.replace("]]>", "]]&gt;")
-        olx_node.text = etree.CDATA("\n" + escaped_block_data + "\n")
+        olx_node.text = etree.CDATA(escaped_block_data)
         return olx_node