diff --git a/base.cfg b/base.cfg
index 89d11bfb..334c38a5 100644
--- a/base.cfg
+++ b/base.cfg
@@ -17,18 +17,6 @@ plone.batching = >=1.1.7
 # plone.app.standardtiles = 2.3.1 # fix https://github.com/plone/plone.app.standardtiles/issues/111
 pycodestyle =
 
-# Robot Testing (see buildout.coredev[5.2]/versions.cfg)
-plone.app.robotframework = 1.5.4
-robotframework = 3.1.2
-robotframework-python3 = 2.9
-robotframework-debuglibrary = 1.2.1
-robotframework-ride = 1.7.4.1
-robotframework-seleniumlibrary = 3.3.1
-robotframework-selenium2library = 3.0.0
-robotframework-selenium2screenshots = 0.8.1
-robotsuite = 2.2.1
-selenium = 3.141.0
-
 [versions:python27]
 # to get codeanalysis working
 build = 0.1
diff --git a/src/collective/collectionfilter/vocabularies.py b/src/collective/collectionfilter/vocabularies.py
index 84fcce34..8abf7207 100644
--- a/src/collective/collectionfilter/vocabularies.py
+++ b/src/collective/collectionfilter/vocabularies.py
@@ -26,6 +26,7 @@
 # Use this EMPTY_MARKER for your custom indexer to index empty criterions.
 EMPTY_MARKER = "__EMPTY__"
 TEXT_IDX = "SearchableText"
+INTEGER_IDXS = []
 GEOLOC_IDX = [
     "latitude",
     "longitude",
@@ -59,7 +60,12 @@
 ] + GEOLOC_IDX  # latitude/longitude is handled as a range filter ... see query.py  # noqa
 DEFAULT_FILTER_TYPE = "single"
 LIST_SCALING = ["No Scaling", "Linear", "Logarithmic"]
-
+TRUTHY = [
+    safe_encode("true"),
+    safe_encode("1"),
+    safe_encode("t"),
+    safe_encode("yes"),
+]
 
 def translate_value(value, *args, **kwargs):
     return translate(_(value), context=getRequest())
@@ -71,30 +77,20 @@ def translate_messagefactory(value, *args, **kwargs):
 
 def make_bool(value):
     """Transform into a boolean value."""
-    truthy = [
-        safe_encode("true"),
-        safe_encode("1"),
-        safe_encode("t"),
-        safe_encode("yes"),
-    ]
+
     if value is None:
         return
     if isinstance(value, bool):
         return value
-    value = safe_encode(value)
-    value = value.lower()
-    if value in truthy:
-        return True
-    else:
-        return False
+    value = safe_encode(value).lower()
+    return value in TRUTHY
 
 
 def yes_no(value):
     """Return i18n message for a value."""
     if value:
         return _(u"Yes")
-    else:
-        return _(u"No")
+    return _(u"No")
 
 
 def get_yes_no_title(item, *args, **kwargs):
@@ -156,6 +152,9 @@ def groupby(self):
                 index_modifier = make_bool
                 display_modifier = get_yes_no_title
 
+            if idx in INTEGER_IDXS:
+                index_modifier = int
+
             # for portal_type or Type we have some special sauce as we need to translate via fti.i18n_domain.  # noqa
             if it == "portal_type":
                 display_modifier = translate_portal_type
diff --git a/test-5.0.x.cfg b/test-5.0.x.cfg
index 85cf5dbc..310c9f1d 100644
--- a/test-5.0.x.cfg
+++ b/test-5.0.x.cfg
@@ -29,4 +29,15 @@ plone.jsonserializer = 0.9.6
 
 plone.formwidget.geolocation = < 2.2.2 # Introduced a dep on CMFPlone 5.2
 
-six = 1.16.0
\ No newline at end of file
+six = 1.16.0
+
+plone.app.robotframework = 1.5.4
+robotframework = 3.1.2
+robotframework-python3 = 2.9
+robotframework-debuglibrary = 1.2.1
+robotframework-ride = 1.7.4.1
+robotframework-seleniumlibrary = 3.3.1
+robotframework-selenium2library = 3.0.0
+robotframework-selenium2screenshots = 0.8.1
+robotsuite = 2.2.1
+selenium = 3.141.0
diff --git a/test-5.1.x.cfg b/test-5.1.x.cfg
index fd6394f4..90c25cf0 100644
--- a/test-5.1.x.cfg
+++ b/test-5.1.x.cfg
@@ -21,4 +21,15 @@ configparser = 3.8.1
 
 plone.formwidget.geolocation = < 2.2.2 # Introduced a dep on CMFPlone 5.2
 
-six = 1.16.0
\ No newline at end of file
+six = 1.16.0
+
+plone.app.robotframework = 1.5.4
+robotframework = 3.1.2
+robotframework-python3 = 2.9
+robotframework-debuglibrary = 1.2.1
+robotframework-ride = 1.7.4.1
+robotframework-seleniumlibrary = 3.3.1
+robotframework-selenium2library = 3.0.0
+robotframework-selenium2screenshots = 0.8.1
+robotsuite = 2.2.1
+selenium = 3.141.0
diff --git a/test-5.2.x.cfg b/test-5.2.x.cfg
index dd888675..dd44bfa1 100644
--- a/test-5.2.x.cfg
+++ b/test-5.2.x.cfg
@@ -18,5 +18,17 @@ test-eggs =
 extensions +=
     flake8-black
 
+[versions]
+plone.app.robotframework = 1.5.4
+robotframework = 3.1.2
+robotframework-python3 = 2.9
+robotframework-debuglibrary = 1.2.1
+robotframework-ride = 1.7.4.1
+robotframework-seleniumlibrary = 3.3.1
+robotframework-selenium2library = 3.0.0
+robotframework-selenium2screenshots = 0.8.1
+robotsuite = 2.2.1
+selenium = 3.141.0
+
 [versions:python3]
 coverage = >=3.7