Skip test on too old PostgreSQL

go.mod

@@ -3,6 +3,7 @@ module github.com/jackc/pgx/v4
 go 1.12
 
 require (
+	github.com/Masterminds/semver/v3 v3.1.1 // indirect
 	github.com/cockroachdb/apd v1.1.0
 	github.com/go-kit/kit v0.10.0
 	github.com/gofrs/uuid v3.2.0+incompatible

go.sum

@@ -3,6 +3,8 @@ cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMT
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/Knetic/govaluate v3.0.1-0.20171022003610-9aa49832a739+incompatible/go.mod h1:r7JcOSlj0wfOMncg0iLm8Leh48TZaKVeNIfJntJ2wa0=
+github.com/Masterminds/semver/v3 v3.1.1 h1:hLg3sBzpNErnxhQtUy/mmLR2I9foDujNK030IGemrRc=
+github.com/Masterminds/semver/v3 v3.1.1/go.mod h1:VPu/7SZ7ePZ3QOrcuXROw5FAcLl4a0cBrbBpGY/8hQs=
 github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
 github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
 github.com/VividCortex/gohistogram v1.0.0/go.mod h1:Pf5mBqqDxYaXu3hDrrU+w6nw50o/4+TcAqDqk/vUH7g=

stdlib/sql_test.go

@@ -12,6 +12,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/Masterminds/semver/v3"
 	"github.com/jackc/pgconn"
 	"github.com/jackc/pgx/v4"
 	"github.com/jackc/pgx/v4/stdlib"
@@ -45,6 +46,37 @@ func skipCockroachDB(t testing.TB, db *sql.DB, msg string) {
 	require.NoError(t, err)
 }
 
+func skipPostgreSQLVersion(t testing.TB, db *sql.DB, constraintStr, msg string) {
+	conn, err := db.Conn(context.Background())
+	require.NoError(t, err)
+	defer conn.Close()
+
+	err = conn.Raw(func(driverConn interface{}) error {
+		conn := driverConn.(*stdlib.Conn).Conn()
+		serverVersionStr := conn.PgConn().ParameterStatus("server_version")
+		// if not PostgreSQL do nothing
+		if serverVersionStr == "" {
+			return nil
+		}
+
+		serverVersion, err := semver.NewVersion(serverVersionStr)
+		if err != nil {
+			return err
+		}
+
+		c, err := semver.NewConstraint(constraintStr)
+		if err != nil {
+			return err
+		}
+
+		if c.Check(serverVersion) {
+			t.Skip(msg)
+		}
+		return nil
+	})
+	require.NoError(t, err)
+}
+
 func testWithAndWithoutPreferSimpleProtocol(t *testing.T, f func(t *testing.T, db *sql.DB)) {
 	t.Run("SimpleProto",
 		func(t *testing.T) {
@@ -1051,6 +1083,7 @@ func TestRegisterConnConfig(t *testing.T) {
 // https://github.com/jackc/pgx/issues/958
 func TestConnQueryRowConstraintErrors(t *testing.T) {
 	testWithAndWithoutPreferSimpleProtocol(t, func(t *testing.T, db *sql.DB) {
+		skipPostgreSQLVersion(t, db, "< 11", "Test requires PG 11+")
 		skipCockroachDB(t, db, "Server does not support deferred constraint (https://github.com/cockroachdb/cockroach/issues/31632)")
 
 		_, err := db.Exec(`create temporary table defer_test (