enable BDD tests for sqlite databases

The database must currently be created by hand and the name handed
in via -DAPI_TEST_DB='sqlite:...'.

test/bdd/steps/nominatim_environment.py

@@ -86,7 +86,10 @@ class NominatimEnvironment:
             be picked up by dotenv and creates a project directory with the
             appropriate website scripts.
         """
-        dsn = 'pgsql:dbname={}'.format(dbname)
+        if dbname.startswith('sqlite:'):
+            dsn = 'sqlite:dbname={}'.format(dbname[7:])
+        else:
+            dsn = 'pgsql:dbname={}'.format(dbname)
         if self.db_host:
             dsn += ';host=' + self.db_host
         if self.db_port:
@@ -197,6 +200,9 @@ class NominatimEnvironment:
         """
         self.write_nominatim_config(self.api_test_db)
 
+        if self.api_test_db.startswith('sqlite:'):
+            return
+
         if not self.api_db_done:
             self.api_db_done = True