fix: return correct transaction level for doesStatementSetTransaction… (#504)

Author: crystall-bitquill

pg/lib/dialect/pg_database_dialect.ts

@@ -174,7 +174,7 @@ export class PgDatabaseDialect implements DatabaseDialect {
 
   doesStatementSetTransactionIsolation(statement: string): TransactionIsolationLevel | undefined {
     if (statement.toLowerCase().includes("set session characteristics as transaction isolation level read uncommitted")) {
-      return TransactionIsolationLevel.TRANSACTION_READ_COMMITTED;
+      return TransactionIsolationLevel.TRANSACTION_READ_UNCOMMITTED;
     }
 
     if (statement.toLowerCase().includes("set session characteristics as transaction isolation level read committed")) {

tests/unit/sql_method_utils.test.ts

@@ -159,7 +159,7 @@ describe("test sql method utils", () => {
     [[" select 1 "], undefined, "pg"],
     [[" select /* COMMENT */ 1 "], undefined, "pg"],
     [[" /* COMMENT */ select /* COMMENT */ 1 "], undefined, "mysql"],
-    [[" set session characteristics as transaction isolation level read uncommitted "], TransactionIsolationLevel.TRANSACTION_READ_COMMITTED, "pg"],
+    [[" set session characteristics as transaction isolation level read uncommitted "], TransactionIsolationLevel.TRANSACTION_READ_UNCOMMITTED, "pg"],
     [[" set session characteristics as transaction isolation level read committed "], TransactionIsolationLevel.TRANSACTION_READ_COMMITTED, "pg"],
     [[" set session characteristics as transaction isolation level repeatable read "], TransactionIsolationLevel.TRANSACTION_REPEATABLE_READ, "pg"],
     [[" set session characteristics as transaction isolation level serializable "], TransactionIsolationLevel.TRANSACTION_SERIALIZABLE, "pg"],