commit cd23784cb42492b4481c003b070f7b8e8988e29a
author Austin Clements <austin@google.com> Thu Mar 17 14:49:50 2022 -0400
committer Austin Clements <austin@google.com> Thu Mar 17 19:14:32 2022 +0000
tree 4597e92bec3a213ffbf98fe29922c622cb2246ce
parent 2512a390557d0cec6c99d4501b03152108c6101b

benchfmt: fix file-does-not-exist error check in tests

Currently, the benchfmt.Files test looks for a specific error message
when checking the handling of nonexistent files. Unfortunately, the
text varies between OSes, making this very hard to do in a robust way.
Change it to just use errors.Is.

This should fix the Plan 9 builder failures.

Change-Id: Ib501cf4c02198a298d6dd902f3593c1887f114c3
Reviewed-on: https://go-review.googlesource.com/c/perf/+/393636
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

benchfmt/files_test.go

diff --git a/benchfmt/files_test.go b/benchfmt/files_test.go
index eb46bfe..923c53a 100644
--- a/benchfmt/files_test.go
+++ b/benchfmt/files_test.go
@@ -5,9 +5,10 @@
 package benchfmt
 
 import (
+	"errors"
+	"io/fs"
 	"os"
 	"strings"
-	"syscall"
 	"testing"
 )
 
@@ -45,17 +46,17 @@
 		}
 
 		err := f.Err()
-		wantErr := ""
-		if len(want) == 1 && strings.HasPrefix(want[0], "err ") {
-			wantErr = want[0][len("err "):]
+		noent := errors.Is(err, fs.ErrNotExist)
+		wantNoent := len(want) == 1 && strings.HasPrefix(want[0], "ErrNotExist")
+		if wantNoent {
 			want = want[1:]
 		}
-		if err == nil && wantErr != "" {
-			t.Errorf("got success, want error %s", wantErr)
-		} else if err != nil && wantErr == "" {
-			t.Errorf("got error %s", err)
-		} else if err != nil && err.Error() != wantErr {
-			t.Errorf("got error %s, want error %s", err, wantErr)
+		if err != nil && !noent {
+			t.Errorf("got unexpected error %s", err)
+		} else if noent && !wantNoent {
+			t.Errorf("got %s, want success", err)
+		} else if !noent && wantNoent {
+			t.Errorf("got success, want ErrNotExist")
 		}
 
 		if len(want) != 0 {
@@ -70,7 +71,7 @@
 	)
 	check(
 		&Files{Paths: []string{"a", "b", "c", "d"}},
-		"a X", "a Y", "b Z", "err open c: "+syscall.ENOENT.Error(),
+		"a X", "a Y", "b Z", "ErrNotExist",
 	)
 
 	// Ambiguous paths.
@@ -82,7 +83,7 @@
 	// AllowStdin.
 	check(
 		&Files{Paths: []string{"-"}},
-		"err open -: "+syscall.ENOENT.Error(),
+		"ErrNotExist",
 	)
 	fakeStdin("BenchmarkIn 1 1 ns/op\n", func() {
 		check(