gnu: khal: Disable failing tests.

* gnu/packages/patches/khal-disable-failing-tests.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/calendar.scm (khal): Use it.

gnu/local.mk

@@ -642,6 +642,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/jbig2dec-ignore-testtest.patch		\
   %D%/packages/patches/jq-CVE-2015-8863.patch			\
   %D%/packages/patches/kdbusaddons-kinit-file-name.patch	\
+  %D%/packages/patches/khal-disable-failing-tests.patch		\
   %D%/packages/patches/khmer-use-libraries.patch                \
   %D%/packages/patches/kmod-module-directory.patch		\
   %D%/packages/patches/kobodeluxe-paths.patch			\

gnu/packages/calendar.scm

@@ -88,6 +88,7 @@ data units.")
     (source (origin
              (method url-fetch)
              (uri (pypi-uri "khal" version))
+             (patches (search-patches "khal-disable-failing-tests.patch"))
              (sha256
               (base32
                "03vy4dp9n43w51mwqjjy08dr5nj7wxqnb085visz3j43vzm42p1f"))))

gnu/packages/patches/khal-disable-failing-tests.patch

@@ -0,0 +1,33 @@
+Disable some tests that are known to fail:
+
+https://github.com/pimutils/khal/issues/546
+https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=844081
+
+diff --git a/tests/khalendar_test.py b/tests/khalendar_test.py
+index fd8dcc6..17732bf 100644
+--- a/tests/khalendar_test.py
++++ b/tests/khalendar_test.py
+@@ -65,6 +65,7 @@ class TestCalendar(object):
+                 else:
+                     mtimes[cal] = mtime
+ 
++    @pytest.mark.xfail
+     def test_db_needs_update(self, coll_vdirs):
+         coll, vdirs = coll_vdirs
+ 
+@@ -321,6 +322,7 @@ class TestDbCreation(object):
+             CalendarCollection(calendars, dbpath=dbpath, locale=aux.locale)
+ 
+ 
++@pytest.mark.xfail
+ def test_default_calendar(coll_vdirs):
+     """test if an update to the vdir is detected by the CalendarCollection"""
+     coll, vdirs = coll_vdirs
+@@ -341,6 +343,7 @@ def test_default_calendar(coll_vdirs):
+     assert len(list(coll.get_events_on(today))) == 0
+ 
+ 
++@pytest.mark.xfail
+ def test_only_update_old_event(coll_vdirs, monkeypatch):
+     coll, vdirs = coll_vdirs
+