if err != nil {
			t.Fatal(err)
		}
		defer w.Close()
		stdout, stderr := runTerminalPassthrough(t, r, w)
		if !stdout {
			t.Errorf("stdout is not a terminal")
		}
		if !stderr {
			t.Errorf("stderr is not a terminal")
		}
	})
}

func runTerminalPassthrough(t *testing.T, r, w *os.File) (stdout, stderr bool) {
	cmd := testenv.Command(t, testGo, "test", "-run=^$")

go test -v -x ./x -timeout 24h -boolflag=true foo -timeout 25h
stdout 'args: foo -timeout 25h'
stdout 'timeout: 24h0m0s$'  # -timeout is unambiguously not a flag, so the real flag wins.

go test -v -x ./x -timeout 24h -boolflag foo -timeout 25h
stdout 'args: foo -test\.timeout=25h0m0s'  # For legacy reasons, '-timeout ' is erroneously rewritten to -test.timeout; see https://golang.org/issue/40763.
stdout 'timeout: 24h0m0s$'  # Actual flag wins.

[short] skip

go test -short -coverpkg=strings strings regexp
! stdout '[^0-9]0\.0%'
stdout  'strings.*coverage:.*[1-9][0-9.]+%'
stdout  'regexp.*coverage:.*[1-9][0-9.]+%'

go test -short -cover strings math regexp
! stdout '[^0-9]0\.0%'
stdout  'strings.*coverage:.*[1-9][0-9.]+%'
stdout  'math.*coverage:.*[1-9][0-9.]+%'

go env GOWORK
stdout '^'$GOPATH'[\\/]src[\\/]go.work$'
go env
stdout '^(set )?GOWORK=''?'$GOPATH'[\\/]src[\\/]go.work''?$'

cd ..
go env GOWORK
! stdout .
go env
stdout 'GOWORK=("")?'

cd src
go env GOWORK
stdout 'go.work'

env GOWORK='off'
go env GOWORK
stdout 'off'

! go env -w GOWORK=off
stderr '^go: GOWORK cannot be modified$'

-- go.work --
go 1.18

use a
-- a/go.mod --

go run .
! stdout panic
! stderr panic
stderr '^ok$'

[cgo] go run main.go
[!cgo] go run main_nocgo.go
! stdout panic
! stderr panic
stderr '^ok$'

go test -v
! stdout panic
! stderr panic
stdout '^ok$'  # 'go test' combines the test's stdout into stderr

go test -v .
! stdout panic
! stderr panic
stdout '^ok$'  # 'go test' combines the test's stdout into stderr

go generate ./nopkg
stdout 'Success a'
! stdout 'Fail'

# Test go generate for package with inconsistent package clauses
# $GOPACKAGE should depend on each file's package clause
go generate ./inconsistent
stdout 'Success a'
stdout 'Success b'
stdout -count=2 'Success c'
! stdout 'Fail'

# Test go generate for syntax errors before and after package clauses
go generate ./syntax

cd a
go install
go version -m $GOBIN/a$GOEXE
stdout '^\tbuild\tvcs=git$'
stdout '^\tbuild\tvcs.modified=true$'
! stdout vcs.revision
! stdout vcs.time
rm $GOBIN/a$GOEXE

# Revision and commit time are tagged for repositories with commits.
exec git add -A
exec git commit -m 'initial commit'
go install
go version -m $GOBIN/a$GOEXE
stdout '^\tbuild\tvcs.revision='
stdout '^\tbuild\tvcs.time='

# the main module).

cp go.mod go.mod.orig

go mod graph
cp stdout graph-1.17.txt
stdout '^example\.com/m example\.com/retract/incompatible@v1\.0\.0$'
stdout '^example\.net/lazy@v0\.1\.0 example\.com/retract/incompatible@v1\.0\.0$'
! stdout 'example\.com/retract/incompatible@v2\.0\.0\+incompatible'

go mod graph -go=1.17
cmp stdout graph-1.17.txt

cmp go.mod go.mod.orig

go get ...test@d7ae1e4
go list -m all
stdout '^github.com/rsc/legacytest v2\.0\.0\+incompatible$'

# v1.2.1-0.pseudo
go get ...test@d2d4c3e
go list -m all
stdout '^github.com/rsc/legacytest v1\.2\.1-0\.\d{14}-d2d4c3ea6623$'

# v1.2.0
go get ...test@9f6f860
go list -m all
stdout '^github.com/rsc/legacytest v1\.2\.0$'

# v1.1.0-pre.0.pseudo
go get ...test@fb3c628
go list -m all

# go help shows overview.
go help
stdout 'Go is a tool'
stdout 'bug.*start a bug report'

# go help bug shows usage for bug
go help bug
stdout 'usage: go bug'
stdout 'bug report'

# go bug help is an error (bug takes no arguments)
! go bug help
stderr 'bug takes no arguments'

# go help mod shows mod subcommands
go help mod
stdout 'go mod <command>'
stdout tidy

# go help mod tidy explains tidy