diff --git a/tests/__init__.py b/tests/__init__.py
index de8b0e7..e051c66 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -62,6 +62,28 @@ PRODID:-//hacksw/handcal//NONSGML v1.0//EN
 ''' + BARE_EVENT_TEMPLATE + u'''
 END:VCALENDAR'''
 
+EVENT_WITH_TIMEZONE_TEMPLATE = '''BEGIN:VCALENDAR
+BEGIN:VTIMEZONE
+TZID:Europe/Rome
+X-LIC-LOCATION:Europe/Rome
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+TZNAME:CEST
+DTSTART:19700329T020000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:19701025T030000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+END:VTIMEZONE
+''' + BARE_EVENT_TEMPLATE + '''
+END:VCALENDAR'''
+
 
 SIMPLE_TEMPLATE = u'''BEGIN:FOO
 UID:{uid}
diff --git a/tests/unit/test_exceptions.py b/tests/unit/test_exceptions.py
new file mode 100644
index 0000000..436f034
--- /dev/null
+++ b/tests/unit/test_exceptions.py
@@ -0,0 +1,14 @@
+from vdirsyncer import exceptions
+
+
+def test_user_error_problems():
+    e = exceptions.UserError('A few problems occured', problems=[
+        'Problem one',
+        'Problem two',
+        'Problem three'
+    ])
+
+    assert 'one' in str(e)
+    assert 'two' in str(e)
+    assert 'three' in str(e)
+    assert 'problems occured' in str(e)
diff --git a/tests/unit/utils/test_vobject.py b/tests/unit/utils/test_vobject.py
index 5d27b63..93c56b4 100644
--- a/tests/unit/utils/test_vobject.py
+++ b/tests/unit/utils/test_vobject.py
@@ -2,8 +2,14 @@
 
 from textwrap import dedent
 
-from tests import BARE_EVENT_TEMPLATE, EVENT_TEMPLATE, VCARD_TEMPLATE, \
-    normalize_item
+import hypothesis.strategies as st
+from hypothesis import given
+
+import pytest
+
+from tests import BARE_EVENT_TEMPLATE, EVENT_TEMPLATE, \
+    EVENT_WITH_TIMEZONE_TEMPLATE, VCARD_TEMPLATE, normalize_item, \
+    uid_strategy
 
 import vdirsyncer.utils.vobject as vobject
 
@@ -195,3 +201,16 @@ def test_multiline_uid_complex():
     assert vobject.Item(a).uid == (u'040000008200E00074C5B7101A82E008000000005'
                                    u'0AAABEEF50DCF001000000062548482FA830A46B9'
                                    u'EA62114AC9F0EF')
+
+
+@pytest.mark.parametrize('template', [EVENT_TEMPLATE,
+                                      EVENT_WITH_TIMEZONE_TEMPLATE,
+                                      VCARD_TEMPLATE])
+@given(uid=st.one_of(st.none(), uid_strategy))
+def test_replace_uid(template, uid):
+    item = vobject.Item(template.format(r=123, uid=123)).with_uid(uid)
+    assert item.uid == uid
+    if uid:
+        assert item.raw.count('\nUID:{}'.format(uid)) == 1
+    else:
+        assert '\nUID:' not in item.raw