Fixed bugs and added test for date range rendering (#488)

* fixed bug for same dates, added unit check for daterange

* fixed local language override in unit test

src/tests/helpers/test_daterange.py

@@ -0,0 +1,57 @@
+from datetime import date
+from django.utils import translation
+from pretix.helpers.daterange import daterange
+
+
+def test_same_day_german():
+    with translation.override('de'):
+        df = date(2003, 2, 1)
+        assert daterange(df, df) == "1. Februar 2003"
+
+
+def test_same_day_english():
+    with translation.override('en'):
+        df = date(2003, 2, 1)
+        assert daterange(df, df) == "Feb. 1st, 2003"
+
+
+def test_same_month_german():
+    with translation.override('de'):
+        df = date(2003, 2, 1)
+        dt = date(2003, 2, 3)
+        assert daterange(df, dt) == "1.–3. Februar 2003"
+
+
+def test_same_month_english():
+    with translation.override('en'):
+        df = date(2003, 2, 1)
+        dt = date(2003, 2, 3)
+        assert daterange(df, dt) == "Feb. 1st – 3rd, 2003"
+
+
+def test_same_year_german():
+    with translation.override('de'):
+        df = date(2003, 2, 1)
+        dt = date(2003, 4, 3)
+        assert daterange(df, dt) == "1. Februar – 3. April 2003"
+
+
+def test_same_year_english():
+    with translation.override('en'):
+        df = date(2003, 2, 1)
+        dt = date(2003, 4, 3)
+        assert daterange(df, dt) == "Feb. 1st – April 3rd, 2003"
+
+
+def test_different_dates_german():
+    with translation.override('de'):
+        df = date(2003, 2, 1)
+        dt = date(2005, 4, 3)
+        assert daterange(df, dt) == "1. Februar 2003 – 3. April 2005"
+
+
+def test_different_dates_english():
+    with translation.override('en'):
+        df = date(2003, 2, 1)
+        dt = date(2005, 4, 3)
+        assert daterange(df, dt) == "Feb. 1, 2003 – April 3, 2005"