--- a/src/pyams_catalog/index.py	Tue Jun 27 13:41:57 2017 +0200
+++ b/src/pyams_catalog/index.py	Wed Jul 12 11:38:51 2017 +0200
@@ -17,7 +17,7 @@
 from datetime import date, datetime
 
 # import interfaces
-from pyams_catalog.interfaces import NO_RESOLUTION, DATE_RESOLUTION
+from pyams_catalog.interfaces import NO_RESOLUTION, DATE_RESOLUTION, MONTH_RESOLUTION
 
 # import packages
 from hypatia.facet import FacetIndex
@@ -75,21 +75,57 @@
 
 
 def get_resolution(value, resolution):
-    """Set resolution of given date or datetime"""
+    """Set resolution of given date or datetime
+
+        >>> from pyams_catalog.interfaces import *
+        >>> from pyams_catalog.index import get_resolution
+        >>> from datetime import date, datetime
+
+    Starting with dates:
+
+        >>> today = date(2017, 7, 11)
+        >>> get_resolution(today, YEAR_RESOLUTION)
+        datetime.date(2017, 1, 1)
+        >>> get_resolution(today, MONTH_RESOLUTION)
+        datetime.date(2017, 7, 1)
+        >>> get_resolution(today, DATE_RESOLUTION)
+        datetime.date(2017, 7, 11)
+
+    Asking for a resolution higher than DATE with a date input only returns date:
+
+        >>> get_resolution(today, MINUTE_RESOLUTION)
+        datetime.date(2017, 7, 11)
+
+    Same examples with datetimes:
+
+        >>> now = datetime(2017, 7, 11, 13, 22, 10)
+        >>> get_resolution(now, YEAR_RESOLUTION)
+        datetime.datetime(2017, 1, 1, 0, 0)
+        >>> get_resolution(now, MONTH_RESOLUTION)
+        datetime.datetime(2017, 7, 1, 0, 0)
+        >>> get_resolution(now, DATE_RESOLUTION)
+        datetime.datetime(2017, 7, 11, 0, 0)
+        >>> get_resolution(now, HOUR_RESOLUTION)
+        datetime.datetime(2017, 7, 11, 13, 0)
+        >>> get_resolution(now, MINUTE_RESOLUTION)
+        datetime.datetime(2017, 7, 11, 13, 22)
+        >>> get_resolution(now, SECOND_RESOLUTION)
+        datetime.datetime(2017, 7, 11, 13, 22, 10)
+    """
     if not value:
         return value
     if resolution < NO_RESOLUTION:
         args = []
-        if isinstance(value, date):
-            resolution = max(resolution, DATE_RESOLUTION)
+        if not isinstance(value, datetime):
+            resolution = min(resolution, DATE_RESOLUTION)
         args.extend(value.timetuple()[:resolution+1])
-        if isinstance(value, date):
-            args.extend([0] * (2 - resolution))
-            value = date(*args)
-        else:
-            args.extend([0] * (5 - resolution))
+        if isinstance(value, datetime):
+            args.extend(([1] * (DATE_RESOLUTION - resolution) + [0] * 5)[:7-len(args)])
             args.append(value.tzinfo)
             value = datetime(*args)
+        else:
+            args.extend([1] * (DATE_RESOLUTION - resolution))
+            value = date(*args)
         return value