diff --git a/src/nti/site/site.py b/src/nti/site/site.py
index da659b5..3fdcb9f 100644
--- a/src/nti/site/site.py
+++ b/src/nti/site/site.py
@@ -379,9 +379,10 @@ def get_target_site(self):
         """
         Returns the target site as defined by this mapping.
         """
+        current_site = getSite()
         site_names = (self.target_site_name,)
-        result = get_site_for_site_names(site_names, site=None)
-        if result is None:
+        result = get_site_for_site_names(site_names, site=current_site)
+        if result is current_site:
             # Invalid mapping
             raise SiteNotFoundError("No site found for %s" % self.target_site_name)
         return result
diff --git a/src/nti/site/tests/test_site.py b/src/nti/site/tests/test_site.py
index 12859e7..9b83e0d 100644
--- a/src/nti/site/tests/test_site.py
+++ b/src/nti/site/tests/test_site.py
@@ -46,11 +46,11 @@
 from nti.site.interfaces import IHostPolicyFolder
 from nti.site.subscribers import threadSiteSubscriber
 from nti.site.transient import HostSiteManager as HSM
-from ..transient import TrivialSite
-from ..site import get_site_for_site_names
-from ..site import find_site_components
-from ..site import get_component_hierarchy
-from ..site import get_component_hierarchy_names
+from nti.site.transient import TrivialSite
+from nti.site.site import get_site_for_site_names
+from nti.site.site import find_site_components
+from nti.site.site import get_component_hierarchy
+from nti.site.site import get_component_hierarchy_names
 
 from nti.site.tests import SharedConfiguringTestLayer
 
@@ -229,10 +229,9 @@ def __init__(self):
         x = list(get_component_hierarchy_names(site, reverse=True))
         assert_that(x, is_(['1', '2']))
 
-from ..site import BTreeLocalSiteManager as BLSM
-from ..site import _LocalAdapterRegistry
-from ..site import BTreeLocalAdapterRegistry
-from ..site import WrongRegistrationTypeError
+from nti.site.site import BTreeLocalSiteManager as BLSM
+from nti.site.site import _LocalAdapterRegistry
+from nti.site.site import BTreeLocalAdapterRegistry
 
 from ZODB import DB
 from ZODB.DemoStorage import DemoStorage
@@ -586,6 +585,27 @@ def test_convert_with_adapter_registered_on_class(self):
         x = comps.getMultiAdapter((object(), 'str'), IFoo)
         assert_that(x, is_(1))
 
+    def test_convert_mark_self_changed(self):
+        comps = BLSM(None)
+
+        comps.btree_threshold = 0
+        comps.adapters.btree_map_threshold = 1
+        comps.adapters.btree_provided_threshold = 0
+        comps.utilities.btree_map_threshold = 0
+
+        comps.registerAdapter(
+                           _foo_factory,
+                           required=(object, type('str')),
+                           provided=IFoo)
+
+        comps.registerAdapter(
+                           _foo_factory2,
+                           required=(object, type(0)),
+                           provided=IFoo)
+
+        x = comps.getMultiAdapter((object(), 'str'), IFoo)
+        assert_that(x, is_(1))
+
 
 def _foo_factory(*args):
     return 1
diff --git a/src/nti/site/tests/test_sync.py b/src/nti/site/tests/test_sync.py
index 955cd7d..3d11f39 100644
--- a/src/nti/site/tests/test_sync.py
+++ b/src/nti/site/tests/test_sync.py
@@ -37,6 +37,7 @@
 from zope.location.interfaces import LocationError
 
 from nti.site.interfaces import ISiteMapping
+from nti.site.interfaces import SiteNotFoundError
 from nti.site.interfaces import IHostPolicyFolder
 
 from nti.site.site import SiteMapping
@@ -371,11 +372,19 @@ def test_site_mapping(self):
             BASE.registerUtility(site_mapping,
                                  provided=ISiteMapping,
                                  name=transient_site)
+            assert_that(site_mapping.get_target_site(),
+                        is_(same_instance(sites[DEMOALPHA.__name__])))
 
             for site_name in (transient_site, DEMOALPHA.__name__):
                 result = get_site_for_site_names((site_name,))
                 assert_that(result, is_(same_instance(sites[DEMOALPHA.__name__])))
 
+            # Invalid mapping raises
+            site_mapping = SiteMapping(source_site_name=transient_site,
+                                       target_site_name=u'nonexistent_site')
+            assert_that(calling(site_mapping.get_target_site),
+                        raises(SiteNotFoundError))
+
             # We can also map persistent sites.
             site_mapping = SiteMapping(source_site_name=DEMOALPHA.__name__,
                                        target_site_name=DEMO.__name__)
diff --git a/tox.ini b/tox.ini
index 9e12381..20aa6d8 100644
--- a/tox.ini
+++ b/tox.ini
@@ -16,3 +16,14 @@ commands =
 deps =
     {[testenv]deps}
     .[docs]
+
+[testenv:coverage]
+usedevelop = true
+basepython =
+    python3.6
+commands =
+    coverage run -m zope.testrunner --test-path=src []
+    coverage report --fail-under=100
+deps =
+    {[testenv]deps}
+    coverage