chore: import upstream snapshot with attribution

testing/generation/function_coverage/postgres.go

@@ -0,0 +1,75 @@
+// Copyright 2024 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/dolthub/go-mysql-server/sql"
+	"github.com/jackc/pgx/v5"
+)
+
+var postgresConnection *pgx.Conn
+
+// QueryPostgres runs the query on a Postgres server and returns the results, along with the OIDs of each result column.
+// This assumes that a valid Postgres (not Doltgres) instance is on port 5432.
+func QueryPostgres(query string) ([]sql.Row, []uint32, error) {
+	var err error
+	ctx := context.Background()
+	if postgresConnection == nil {
+		connectionString := fmt.Sprintf("postgres://postgres:password@127.0.0.1:%d/", 5432)
+		postgresConnection, err = pgx.Connect(ctx, connectionString)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+	r, err := postgresConnection.Query(ctx, query)
+	if err != nil {
+		return nil, nil, err
+	}
+	var oids []uint32
+	for _, desc := range r.FieldDescriptions() {
+		oids = append(oids, desc.DataTypeOID)
+	}
+	var allRows []sql.Row
+	for r.Next() {
+		if err = r.Err(); err != nil {
+			return nil, nil, err
+		}
+		row, err := r.Values()
+		if err != nil {
+			return nil, nil, err
+		}
+		allRows = append(allRows, row)
+	}
+	return allRows, oids, r.Err()
+}
+
+// ExecPostgres runs the query on a Postgres server without checking the results. This assumes that a valid Postgres
+// (not Doltgres) instance is on port 5432.
+func ExecPostgres(query string) error {
+	var err error
+	ctx := context.Background()
+	if postgresConnection == nil {
+		connectionString := fmt.Sprintf("postgres://postgres:password@127.0.0.1:%d/", 5432)
+		postgresConnection, err = pgx.Connect(ctx, connectionString)
+		if err != nil {
+			return err
+		}
+	}
+	_, err = postgresConnection.Exec(ctx, query)
+	return err
+}