diff --git a/metrik/conf.py b/metrik/conf.py
index db76628..15422f1 100644
--- a/metrik/conf.py
+++ b/metrik/conf.py
@@ -15,7 +15,7 @@ def get_default_conf():
 # Normally it's terrible practice to put static calls into the signature,
 # but this is safe (for now) since the get_config_locations() won't change
 # during a run. I.e. it starts up and that's the only time it's ever needed.
-def get_config(extra_locations=get_config_locations()):
+def get_config(extra_locations=get_config_locations(), is_test=False):
     config = RawConfigParser()
 
     config.readfp(get_default_conf())
@@ -28,7 +28,7 @@ def get_config(extra_locations=get_config_locations()):
     # end-users, but I'm calling it a special case for testing
     is_travis = 'TRAVIS_BUILD_NUMBER' in os.environ
     is_pytest = hasattr(sys, '_called_from_test')
-    if is_pytest or is_travis:
+    if is_pytest or is_travis or is_test:
         config.set('metrik', 'mongo_database', 'metrik-test')
 
     return config
diff --git a/test/mongo_test.py b/test/mongo_test.py
index d70feb2..24ebfff 100644
--- a/test/mongo_test.py
+++ b/test/mongo_test.py
@@ -7,7 +7,7 @@ from metrik.targets.mongo import MongoTarget
 
 class MongoTest(TestCase):
     def setUp(self):
-        config = get_config()
+        config = get_config(is_test=True)
         self.client = MongoClient(
             host=config.get('metrik', 'mongo_host'),
             port=config.getint('metrik', 'mongo_port'))
@@ -15,7 +15,7 @@ class MongoTest(TestCase):
 
     def tearDown(self):
         super(MongoTest, self).tearDown()
-        config = get_config()
+        config = get_config(is_test=True)
         self.client.drop_database(config.get('metrik', 'mongo_database'))
 
 
diff --git a/test/test_conf.py b/test/test_conf.py
index 2d7596f..5871514 100644
--- a/test/test_conf.py
+++ b/test/test_conf.py
@@ -7,4 +7,14 @@ class ConfigurationTest(TestCase):
 
     def test_config_returns_values(self):
         config = get_config([])
-        assert config is not None
\ No newline at end of file
+        assert config is not None
+
+    def test_config_manual_test_instruction(self):
+        config = get_config()
+        self.assertEqual(config.get('metrik', 'mongo_database'), 'metrik')
+
+        config = get_config(is_test=False)
+        self.assertEqual(config.get('metrik', 'mongo_database'), 'metrik')
+
+        config = get_config(is_test=True)
+        self.assertEqual(config.get('metrik', 'mongo_database'), 'metrik-test')
\ No newline at end of file
diff --git a/test/test_merge.py b/test/test_merge.py
index 38881e4..7541bc0 100644
--- a/test/test_merge.py
+++ b/test/test_merge.py
@@ -33,3 +33,14 @@ class MergeTest(MongoTest):
         assert item_retrieved is not None
         assert item_retrieved['string'] == item_string
 
+    def test_merge_is_nondestructive(self):
+        item1_id = self.db2[self.collection_name].save({})
+        item2_id = self.db[self.collection_name].save({})
+
+        assert len(list(self.db[self.collection_name].find())) == 1
+        assert len(list(self.db2[self.collection_name].find())) == 1
+
+        merge(self.client, self.client,
+              self.db.name, self.db2.name)
+        assert len(list(self.db[self.collection_name].find())) == 0
+        assert len(list(self.db2[self.collection_name].find())) == 2
\ No newline at end of file