diff --git a/conda-requirements.txt b/conda-requirements.txt
index 3af0ec5003..fea36e4546 100644
--- a/conda-requirements.txt
+++ b/conda-requirements.txt
@@ -4,7 +4,7 @@
 # Mandatory dependencies
 biggus>=0.14.0
 cartopy
-matplotlib=1.3.1
+matplotlib
 netcdf4
 numpy
 pyke
diff --git a/lib/iris/tests/unit/coord_categorisation/test_add_hour.py b/lib/iris/tests/unit/coord_categorisation/test_add_hour.py
index 737d8a650b..f4e2a0759d 100644
--- a/lib/iris/tests/unit/coord_categorisation/test_add_hour.py
+++ b/lib/iris/tests/unit/coord_categorisation/test_add_hour.py
@@ -33,6 +33,9 @@
 
 
 class Test_add_hour(tests.IrisTest):
+    def calendar(self):
+        return 'gregorian'
+
     def setUp(self):
         # make a series of 'hour numbers' for the time
         hour_numbers = np.arange(0, 200, 5, dtype=np.int32)
@@ -44,7 +47,7 @@ def setUp(self):
 
         time_coord = iris.coords.DimCoord(
             hour_numbers, standard_name='time',
-            units=cf_units.Unit('hours since epoch', 'gregorian'))
+            units=cf_units.Unit('hours since epoch', self.calendar()))
         cube.add_dim_coord(time_coord, 0)
 
         self.hour_numbers = hour_numbers
@@ -88,5 +91,9 @@ def test_basic(self):
         self.assertEqual(cube.coord(coord_name), expected_coord)
 
 
+class Test_add_hour_360_day(Test_add_hour):
+    def calendar(self):
+        return '360_day'
+
 if __name__ == '__main__':
     tests.main()