fix tests

Author: kshvakov

clickhouse_columnar_test.go

@@ -60,7 +60,7 @@ func Test_ColumnarInsert(t *testing.T) {
 	if connect, err := clickhouse.OpenDirect("tcp://127.0.0.1:9000?debug=true"); assert.NoError(t, err) {
 		{
 			connect.Begin()
-			stmt, _ := connect.Prepare("DROP TABLE clickhouse_test_columnar_insert")
+			stmt, _ := connect.Prepare("DROP TABLE IF EXISTS clickhouse_test_columnar_insert")
 			stmt.Exec([]driver.Value{})
 			connect.Commit()
 		}

clickhouse_direct_test.go

@@ -85,7 +85,7 @@ func Test_DirectInsert(t *testing.T) {
 		{
 			var (
 				tx, _   = connect.Begin()
-				stmt, _ = connect.Prepare("DROP TABLE clickhouse_test_direct_insert")
+				stmt, _ = connect.Prepare("DROP TABLE IF EXISTS clickhouse_test_direct_insert")
 			)
 			stmt.Exec([]driver.Value{})
 			tx.Commit()
@@ -204,7 +204,7 @@ func Test_DirectArrayT(t *testing.T) {
 		{
 			var (
 				tx, _   = connect.Begin()
-				stmt, _ = connect.Prepare("DROP TABLE clickhouse_test_direct_array")
+				stmt, _ = connect.Prepare("DROP TABLE IF EXISTS clickhouse_test_direct_array")
 			)
 			stmt.Exec([]driver.Value{})
 			tx.Commit()