diff --git a/src/icalendar/tests/calendars/pr_480_summary_with_colon.ics b/src/icalendar/tests/calendars/pr_480_summary_with_colon.ics
index 3494aec..96b6917 100644
--- a/src/icalendar/tests/calendars/pr_480_summary_with_colon.ics
+++ b/src/icalendar/tests/calendars/pr_480_summary_with_colon.ics
@@ -5,4 +5,3 @@ END:VEVENT
 BEGIN:VEVENT
 SUMMARY:Another event with a ': ' in the summary
 END:VEVENT
-END:VCALENDAR
diff --git a/src/icalendar/tests/timezoned.ics b/src/icalendar/tests/calendars/timezoned.ics
similarity index 100%
rename from src/icalendar/tests/timezoned.ics
rename to src/icalendar/tests/calendars/timezoned.ics
diff --git a/src/icalendar/tests/conftest.py b/src/icalendar/tests/conftest.py
index c823a01..4a954a2 100644
--- a/src/icalendar/tests/conftest.py
+++ b/src/icalendar/tests/conftest.py
@@ -23,6 +23,8 @@ class DataSource:
         """Parse a file and return the result stored in the attribute."""
         source_file = attribute.replace('-', '_') + '.ics'
         source_path = os.path.join(self._data_source_folder, source_file)
+        if not os.path.isfile(source_path):
+            raise AttributeError(f"{source_path} does not exist.")
         with open(source_path, 'rb') as f:
             raw_ics = f.read()
         source = self._parser(raw_ics)
@@ -84,9 +86,10 @@ def in_timezone(request):
     (data, key)
     for data in [CALENDARS, TIMEZONES, EVENTS]
     for key in data.keys() if key not in
-    (
+    ( # exclude broken calendars here
         "big_bad_calendar", "issue_104_broken_calendar", "small_bad_calendar",
-        "multiple_calendar_components")
+        "multiple_calendar_components", "pr_480_summary_with_colon"
+    )
 ])
 def ics_file(request):
     """An example ICS file."""
diff --git a/src/icalendar/tests/test_timezoned.py b/src/icalendar/tests/test_timezoned.py
index 2f284f8..ee3ec11 100644
--- a/src/icalendar/tests/test_timezoned.py
+++ b/src/icalendar/tests/test_timezoned.py
@@ -14,7 +14,7 @@ class TestTimezoned(unittest.TestCase):
 
     def test_create_from_ical_zoneinfo(self):
         directory = os.path.dirname(__file__)
-        with open(os.path.join(directory, 'timezoned.ics'), 'rb') as fp:
+        with open(os.path.join(directory, 'calendars', 'timezoned.ics'), 'rb') as fp:
             data = fp.read()
         cal = icalendar.Calendar.from_ical(data)
 
@@ -47,7 +47,7 @@ class TestTimezoned(unittest.TestCase):
 
     def test_create_from_ical_pytz(self):
         directory = os.path.dirname(__file__)
-        with open(os.path.join(directory, 'timezoned.ics'), 'rb') as fp:
+        with open(os.path.join(directory, 'calendars', 'timezoned.ics'), 'rb') as fp:
             data = fp.read()
         cal = icalendar.Calendar.from_ical(data)