Test-only fix: normalize white space when comparing output of comment.getText().

Needed to not fail with newer `plone.outputfilters` from this PR: https://github.com/plone/plone.outputfilters/pull/49
Comments go through the outputfilters, and the new branch calls `soup.prettify()` from `Beautifulsoup`, leading to more white space.
Sample test failures on Jenkins, see https://jenkins.plone.org/job/plip-plip-image-srcsets-3.8/5/#showFailuresLink

```
'<p>\n Go to http://www.plone.org\n</p>' != '<p>Go to http://www.plone.org</p>'
- <p>
-  Go to http://www.plone.org
? ^                          ^
+ <p>Go to http://www.plone.org</p>? ^^^                          ^^^^
- </p>

  File "/srv/python3.8/lib/python3.8/unittest/case.py", line 60, in testPartExecutor
    yield
  File "/srv/python3.8/lib/python3.8/unittest/case.py", line 676, in run
    self._callTestMethod(testMethod)
  File "/srv/python3.8/lib/python3.8/unittest/case.py", line 633, in _callTestMethod
    method()
  File "/home/jenkins/.buildout/eggs/cp38/plone.app.discussion-4.0.0a7-py3.8.egg/plone/app/discussion/tests/test_comment.py", line 180, in test_getText_doesnt_link
    self.assertEqual(
  File "/srv/python3.8/lib/python3.8/unittest/case.py", line 912, in assertEqual
    assertion_func(first, second, msg=msg)
  File "/srv/python3.8/lib/python3.8/unittest/case.py", line 1292, in assertMultiLineEqual
    self.fail(self._formatMessage(msg, standardMsg))
  File "/srv/python3.8/lib/python3.8/unittest/case.py", line 753, in fail
    raise self.failureException(msg)
```

news/49.bugfix

@@ -0,0 +1,3 @@
+Test-only fix: normalize white space when comparing output of ``comment.getText()``.
+Needed to not fail with newer ``plone.outputfilters``.
+[maurits]

plone/app/discussion/tests/test_comment.py

@@ -18,6 +18,22 @@ logger = logging.getLogger("plone.app.discussion.tests")
 logger.addHandler(logging.StreamHandler())
 
 
+def normalize(value):
+    # Strip all white spaces of every line, then join on one line.
+    # But try to avoid getting 'Go to<a href' instead of 'Go to <a href'.
+    lines = []
+    for line in value.splitlines():
+        line = line.strip()
+        if (
+            line.startswith("<")
+            and not line.startswith("</")
+            and not line.startswith("<br")
+        ):
+            line = " " + line
+        lines.append(line)
+    return "".join(lines).strip()
+
+
 class CommentTest(unittest.TestCase):
 
     layer = PLONE_APP_DISCUSSION_INTEGRATION_TESTING
@@ -156,7 +172,7 @@ class CommentTest(unittest.TestCase):
         comment1 = createObject("plone.Comment")
         comment1.text = "First paragraph\n\nSecond_paragraph"
         self.assertEqual(
-            "".join(comment1.getText().split()),
+            normalize(comment1.getText()),
             "<p>First paragraph<br><br>Second_paragraph</p>",
         )
 
@@ -164,7 +180,7 @@ class CommentTest(unittest.TestCase):
         comment1 = createObject("plone.Comment")
         comment1.text = "<b>Got HTML?</b>"
         self.assertEqual(
-            comment1.getText(),
+            normalize(comment1.getText()),
             "<p>&lt;b&gt;Got HTML?&lt;/b&gt;</p>",
         )
 
@@ -172,13 +188,13 @@ class CommentTest(unittest.TestCase):
         comment1 = createObject("plone.Comment")
         comment1.text = "Umlaute sind ä, ö und ü."
         out = b"<p>Umlaute sind \xc3\xa4, \xc3\xb6 und \xc3\xbc.</p>"
-        self.assertEqual(comment1.getText(), out.decode("utf8"))
+        self.assertEqual(normalize(comment1.getText()), out.decode("utf8"))
 
     def test_getText_doesnt_link(self):
         comment1 = createObject("plone.Comment")
         comment1.text = "Go to http://www.plone.org"
         self.assertEqual(
-            comment1.getText(),
+            normalize(comment1.getText()),
             "<p>Go to http://www.plone.org</p>",
         )
 
@@ -187,7 +203,7 @@ class CommentTest(unittest.TestCase):
         comment1.text = "Go to http://www.plone.org"
         comment1.mime_type = "text/x-web-intelligent"
         self.assertEqual(
-            comment1.getText(),
+            normalize(comment1.getText()),
             'Go to <a href="http://www.plone.org" '
             + 'rel="nofollow">http://www.plone.org</a>',
         )
@@ -197,7 +213,7 @@ class CommentTest(unittest.TestCase):
         comment1.text = 'Go to <a href="http://www.plone.org">plone.org</a>'
         comment1.mime_type = "text/html"
         self.assertEqual(
-            comment1.getText(),
+            normalize(comment1.getText()),
             'Go to <a href="http://www.plone.org">plone.org</a>',
         )