1 // Copyright 2009 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // This file implements a simple printer performance benchmark:
6 // go test -bench=BenchmarkPrint
20 var testfile *ast.File
22 func testprint(out io.Writer, file *ast.File) {
23 if err := (&Config{TabIndent | UseSpaces, 8, 0}).Fprint(out, fset, file); err != nil {
24 log.Fatalf("print error: %s", err)
28 // cannot initialize in init because (printer) Fprint launches goroutines.
30 const filename = "testdata/parser.go"
32 src, err := ioutil.ReadFile(filename)
37 file, err := parser.ParseFile(fset, filename, src, parser.ParseComments)
44 if !bytes.Equal(buf.Bytes(), src) {
45 log.Fatalf("print error: %s not idempotent", filename)
51 func BenchmarkPrint(b *testing.B) {
55 for i := 0; i < b.N; i++ {
56 testprint(ioutil.Discard, testfile)