diff --git a/python/plugins/db_manager/db_plugins/postgis/plugin_test.py b/python/plugins/db_manager/db_plugins/postgis/plugin_test.py
index b11a04e2a3e..1d869eb7e84 100644
--- a/python/plugins/db_manager/db_plugins/postgis/plugin_test.py
+++ b/python/plugins/db_manager/db_plugins/postgis/plugin_test.py
@@ -41,42 +41,89 @@ from db_manager.db_plugins.postgis.connector import PostGisDBConnector
 
 class TestDBManagerPostgisPlugin(unittest.TestCase):
 
+    @classmethod
+    def setUpClass(self):
+        self.old_pgdatabase_env = os.environ.get('PGDATABASE')
+        self.testdb = os.environ.get('QGIS_PGTEST_DB') or 'qgis_test'
+        os.environ['PGDATABASE'] = self.testdb
+
+        # Create temporary service file
+        self.old_pgservicefile_env = os.environ.get('PGSERVICEFILE')
+        self.tmpservicefile = '/tmp/qgis-test-{}-pg_service.conf'.format(os.getpid())
+        os.environ['PGSERVICEFILE'] = self.tmpservicefile
+
+        f = open(self.tmpservicefile, "w")
+        f.write("[dbmanager]\ndbname={}\n".format(self.testdb))
+        # TODO: add more things if PGSERVICEFILE was already set ?
+        f.close()
+
+    @classmethod
+    def tearDownClass(self):
+        # Restore previous env variables if needed
+        if self.old_pgdatabase_env:
+            os.environ['PGDATABASE'] = self.old_pgdatabase_env
+        if self.old_pgservicefile_env:
+            os.environ['PGSERVICEFILE'] = self.old_pgservicefile_env
+        # Remove temporary service file
+        os.unlink(self.tmpservicefile)
+
     # See https://issues.qgis.org/issues/16625
-    # and https://issues.qgis.org/issues/10600
 
-    def test_rasterTable(self):
+    def test_rasterTableGdalURI(self):
 
-        testdb = os.environ.get('QGIS_PGTEST_DB') or 'qgis_test'
-        os.environ['PGDATABASE'] = testdb
+        def check_rasterTableGdalURI(expected_dbname):
+            tables = database.tables()
+            raster_tables_count = 0
+            for tab in tables:
+                if tab.type == Table.RasterType:
+                    raster_tables_count += 1
+                    gdalUri = tab.gdalUri()
+                    m = re.search(' dbname=([^ ]*) ', gdalUri)
+                    self.assertTrue(m)
+                    actual_dbname = m.group(1)
+                    self.assertEqual(actual_dbname, expected_dbname)
+                #print(tab.type)
+                #print(tab.quotedName())
+                #print(tab)
+
+            # We need to make sure a database is created with at
+            # least one raster table !
+            self.assertEqual(raster_tables_count, 1)
 
         obj = QObject() # needs to be kept alive
+
+        # Test for empty URI
+        # See https://issues.qgis.org/issues/16625
+        # and https://issues.qgis.org/issues/10600
+
+        expected_dbname = self.testdb
+        os.environ['PGDATABASE'] = expected_dbname
+
         database = PGDatabase(obj, QgsDataSourceUri())
         self.assertIsInstance(database, PGDatabase)
 
         uri = database.uri()
         self.assertEqual(uri.host(), '')
         self.assertEqual(uri.username(), '')
-        expected_user = os.environ.get('PGUSER') or os.environ.get('USER')
-        expected_dbname = os.environ.get('PGDATABASE') or expected_user
         self.assertEqual(uri.database(), expected_dbname)
+        self.assertEqual(uri.service(), '')
 
-        tables = database.tables()
-        raster_tables_count = 0
-        for tab in tables:
-            if tab.type == Table.RasterType:
-                raster_tables_count += 1
-                gdalUri = tab.gdalUri()
-                m = re.search(' dbname=([^ ]*) ', gdalUri)
-                self.assertTrue(m)
-                actual_dbname = m.group(1)
-                self.assertEqual(actual_dbname, expected_dbname)
-            #print(tab.type)
-            #print(tab.quotedName())
-            #print(tab)
+        check_rasterTableGdalURI(expected_dbname)
 
-        # We need to make sure a database is created with at
-        # least one raster table !
-        self.assertEqual(raster_tables_count, 1)
+        # Test for service-only URI
+        # See https://issues.qgis.org/issues/16626
+
+        os.environ['PGDATABASE'] = 'fake'
+        database = PGDatabase(obj, QgsDataSourceUri('service=dbmanager'))
+        self.assertIsInstance(database, PGDatabase)
+
+        uri = database.uri()
+        self.assertEqual(uri.host(), '')
+        self.assertEqual(uri.username(), '')
+        self.assertEqual(uri.database(), '')
+        self.assertEqual(uri.service(), 'dbmanager')
+
+        check_rasterTableGdalURI(expected_dbname)
 
 
 if __name__ == '__main__':