Remove skip test for missing json type

All supported versions of PostgreSQL now have json type.

example_json_test.go

@@ -2,6 +2,7 @@ package pgx_test
 
 import (
 	"fmt"
+
 	"github.com/jackc/pgx"
 )
 
@@ -12,13 +13,6 @@ func Example_JSON() {
 		return
 	}
 
-	if _, ok := conn.PgTypes[pgx.JSONOID]; !ok {
-		// No JSON type -- must be running against very old PostgreSQL
-		// Pretend it works
-		fmt.Println("John", 42)
-		return
-	}
-
 	type person struct {
 		Name string `json:"name"`
 		Age  int    `json:"age"`

stdlib/sql_test.go

@@ -3,9 +3,10 @@ package stdlib_test
 import (
 	"bytes"
 	"database/sql"
+	"testing"
+
 	"github.com/jackc/pgx"
 	"github.com/jackc/pgx/stdlib"
-	"testing"
 )
 
 func openDB(t *testing.T) *sql.DB {
@@ -497,10 +498,6 @@ func TestConnQueryJSONIntoByteSlice(t *testing.T) {
 	db := openDB(t)
 	defer closeDB(t, db)
 
-	if !serverHasJSON(t, db) {
-		t.Skip("Skipping due to server's lack of JSON type")
-	}
-
 	_, err := db.Exec(`
 		create temporary table docs(
 			body json not null
@@ -537,10 +534,6 @@ func TestConnExecInsertByteSliceIntoJSON(t *testing.T) {
 	db := openDB(t)
 	defer closeDB(t, db)
 
-	if !serverHasJSON(t, db) {
-		t.Skip("Skipping due to server's lack of JSON type")
-	}
-
 	_, err := db.Exec(`
 		create temporary table docs(
 			body json not null
@@ -575,15 +568,6 @@ func TestConnExecInsertByteSliceIntoJSON(t *testing.T) {
 	ensureConnValid(t, db)
 }
 
-func serverHasJSON(t *testing.T, db *sql.DB) bool {
-	var hasJSON bool
-	err := db.QueryRow(`select exists(select 1 from pg_type where typname='json')`).Scan(&hasJSON)
-	if err != nil {
-		t.Fatalf("db.QueryRow unexpectedly failed: %v", err)
-	}
-	return hasJSON
-}
-
 func TestTransactionLifeCycle(t *testing.T) {
 	db := openDB(t)
 	defer closeDB(t, db)