From 8893175c3b5267f1eb70c518b5de6f03037c4d03 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Daniel=20Mart=C3=AD?= Date: Sun, 6 Mar 2022 11:26:11 +0000 Subject: [PATCH] flag: make tests silent MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit A few of the tests were printing garbage to stderr, since FlagSet's default Output is os.Stderr: $ go test flag provided but not defined: -x invalid value "1" for flag -v: test error Usage of test: flag needs an argument: -b Usage of test: -b usage PASS ok flag 0.008s Add the remaining SetOutput(io.Discard) method calls. Note that TestUserDefinedFunc was a tricky one. Even with the added SetOutput calls, the last part of the test would still print usage text to stderr. It took me a while to figure out the problem was copying FlagSet. I've filed go.dev/issue/51507 to record this particular sharp edge, and the test code now avoids making FlagSet copies to avoid the bug. Change-Id: I323f24091b98386312aa72df3eb890af6625628d Reviewed-on: https://go-review.googlesource.com/c/go/+/390234 Trust: Daniel Martí Run-TryBot: Daniel Martí TryBot-Result: Gopher Robot Reviewed-by: Ian Lance Taylor --- src/flag/export_test.go | 6 +++++- src/flag/flag_test.go | 9 ++++++--- 2 files changed, 11 insertions(+), 4 deletions(-) diff --git a/src/flag/export_test.go b/src/flag/export_test.go index 838cfaf6a4..9ef93ed6c5 100644 --- a/src/flag/export_test.go +++ b/src/flag/export_test.go @@ -4,7 +4,10 @@ package flag -import "os" +import ( + "io" + "os" +) // Additional routines compiled into the package only during testing. @@ -15,6 +18,7 @@ var DefaultUsage = Usage // exit the program. func ResetForTesting(usage func()) { CommandLine = NewFlagSet(os.Args[0], ContinueOnError) + CommandLine.SetOutput(io.Discard) CommandLine.Usage = commandLineUsage Usage = usage } diff --git a/src/flag/flag_test.go b/src/flag/flag_test.go index 5835fcf22c..d5c443d3c6 100644 --- a/src/flag/flag_test.go +++ b/src/flag/flag_test.go @@ -246,6 +246,7 @@ func (f *flagVar) Set(value string) error { func TestUserDefined(t *testing.T) { var flags FlagSet flags.Init("test", ContinueOnError) + flags.SetOutput(io.Discard) var v flagVar flags.Var(&v, "v", "usage") if err := flags.Parse([]string{"-v", "1", "-v", "2", "-v=3"}); err != nil { @@ -261,8 +262,8 @@ func TestUserDefined(t *testing.T) { } func TestUserDefinedFunc(t *testing.T) { - var flags FlagSet - flags.Init("test", ContinueOnError) + flags := NewFlagSet("test", ContinueOnError) + flags.SetOutput(io.Discard) var ss []string flags.Func("v", "usage", func(s string) error { ss = append(ss, s) @@ -286,7 +287,8 @@ func TestUserDefinedFunc(t *testing.T) { t.Errorf("usage string not included: %q", usage) } // test Func error - flags = *NewFlagSet("test", ContinueOnError) + flags = NewFlagSet("test", ContinueOnError) + flags.SetOutput(io.Discard) flags.Func("v", "usage", func(s string) error { return fmt.Errorf("test error") }) @@ -335,6 +337,7 @@ func (b *boolFlagVar) IsBoolFlag() bool { func TestUserDefinedBool(t *testing.T) { var flags FlagSet flags.Init("test", ContinueOnError) + flags.SetOutput(io.Discard) var b boolFlagVar var err error flags.Var(&b, "b", "usage") -- 2.50.0