Add test file for equality tests

src/icalendar/cal.py

@@ -465,6 +465,11 @@ class Component(CaselessDict):
 
         return True
 
+    def copy(self):
+        """Create a copy of the component."""
+        copy = super().copy()
+        copy.subcomponents = self.subcomponents[:]
+        return copy
 
 #######################################
 # components defined in RFC 5545

src/icalendar/tests/test_equality.py

@@ -0,0 +1,43 @@
+"""Test the equality and inequality of components."""
+import copy
+import pytz
+
+
+def test_parsed_calendars_are_equal(ics_file):
+    """Ensure that a calendar equals the same calendar."""
+    copy_of_calendar = ics_file.__class__.from_ical(ics_file.to_ical())
+    assert copy_of_calendar == ics_file
+    assert not copy_of_calendar != ics_file
+
+
+def test_copies_are_equal(ics_file):
+    """Ensure that copies are equal."""
+    assert ics_file.copy() == ics_file.copy()
+    assert ics_file.copy() == ics_file
+    assert not ics_file.copy() != ics_file.copy()
+    assert not ics_file.copy() != ics_file
+
+def test_deep_copies_are_equal(ics_file):
+    """Ensure that deep copies are equal."""
+    try:
+        assert copy.deepcopy(ics_file) == copy.deepcopy(ics_file)
+        assert copy.deepcopy(ics_file) == ics_file
+        assert not copy.deepcopy(ics_file) != copy.deepcopy(ics_file)
+        assert not copy.deepcopy(ics_file) != ics_file
+    except pytz.UnknownTimeZoneError:
+        # Ignore errors when a custom time zone is used.
+        # This is still covered by the parsing test.
+        pass
+
+
+def test_a_components_copy_also_copies_subcomponents(calendars):
+    """A calendar's copy does not have the identical subcompoenets!
+
+    We expect to be able to modify a copy but not its values.
+    """
+    cal = calendars.timezoned
+    copy = cal.copy()
+    assert copy is not cal
+    assert copy.subcomponents
+    assert copy.subcomponents is not cal.subcomponents
+    assert copy.subcomponents == cal.subcomponents

src/icalendar/tests/test_examples.py

@@ -3,7 +3,7 @@
 import datetime
 from icalendar import Calendar, Event
 import pytest
-import copy
+
 
 def test_creating_calendar_with_unicode_fields(calendars, utc):
     ''' create a calendar with events that contain unicode characters in their fields '''
@@ -37,17 +37,3 @@ def test_creating_calendar_with_unicode_fields(calendars, utc):
     cal.add_component(event2)
 
     assert cal.to_ical() == calendars.created_calendar_with_unicode_fields.raw_ics
-
-
-def test_parsed_calendars_are_equal(ics_file):
-    """Ensure that a calendar equals the same calendar."""
-    copy_of_calendar = ics_file.__class__.from_ical(ics_file.to_ical())
-    assert copy_of_calendar == ics_file
-
-def test_copies_are_equal(ics_file):
-    """Ensure that copies are equal."""
-    assert ics_file.copy() == ics_file.copy() == ics_file
-
-def test_deep_copies_are_equal(ics_file):
-    """Ensure that deep copies are equal."""
-    assert copy.deepcopy(ics_file) == copy.deepcopy(ics_file) == ics_file