add unit tests for new check_database code

test/python/test_db_connection.py

@@ -20,12 +20,31 @@ def test_connection_table_exists(db, temp_db_cursor):
     assert db.table_exists('foobar') == True
 
 
+def test_connection_index_exists(db, temp_db_cursor):
+    assert db.index_exists('some_index') == False
+
+    temp_db_cursor.execute('CREATE TABLE foobar (id INT)')
+    temp_db_cursor.execute('CREATE INDEX some_index ON foobar(id)')
+
+    assert db.index_exists('some_index') == True
+    assert db.index_exists('some_index', table='foobar') == True
+    assert db.index_exists('some_index', table='bar') == False
+
+
+def test_connection_server_version_tuple(db):
+    ver = db.server_version_tuple()
+
+    assert isinstance(ver, tuple)
+    assert len(ver) == 2
+    assert ver[0] > 8
+
 def test_cursor_scalar(db, temp_db_cursor):
     temp_db_cursor.execute('CREATE TABLE dummy (id INT)')
 
     with db.cursor() as cur:
         assert cur.scalar('SELECT count(*) FROM dummy') == 0
 
+
 def test_cursor_scalar_many_rows(db):
     with db.cursor() as cur:
         with pytest.raises(RuntimeError):