unquote scripts/exec.txt

# The module uses testscript itself.
# Use the checked out module, based on where the test binary ran.
go mod edit -replace=github.com/rogpeppe/go-internal=${GOINTERNAL_MODULE}
go mod tidy

# First, a 'go test' run without coverage.
go test -vet=off
stdout 'PASS'
! stdout 'coverage'

# Then, a 'go test' run with -coverprofile.
# The total coverage after merging profiles should end up being 100%.
# Marking all printlns as covered requires all edge cases to work well.
go test -vet=off -coverprofile=cover.out -v
stdout 'PASS'
stdout 'coverage: 100\.0%'
! stdout 'malformed coverage' # written by "go test" if cover.out is invalid
exists cover.out

-- go.mod --
module test

go 1.15
-- foo.go --
package foo

import "os"

func foo1() int {
	switch os.Args[1] {
	case "1":
		println("first path")
	case "2":
		println("second path")
	default:
		println("third path")
	}
	return 1
}
-- foo_test.go --
package foo

import (
	"os"
	"testing"

	"github.com/rogpeppe/go-internal/gotooltest"
	"github.com/rogpeppe/go-internal/testscript"
)

func TestMain(m *testing.M) {
	// Note that here we still use RunMain, which is the older deprecated API,
	// to sanity check that it works OK.
	os.Exit(testscript.RunMain(m, map[string] func() int{
		"foo": foo1,
	}))
}

func TestFoo(t *testing.T) {
	p := testscript.Params{
		Dir: "scripts",
	}
	if err := gotooltest.Setup(&p); err != nil {
		t.Fatal(err)
	}
	testscript.Run(t, p)
}
-- scripts/exec.txt --
># Note that foo always fails, to prevent "go build" from doing anything.
>
># Running the command directly; trigger the first path.
>! foo 1
>
># Running the command via exec; trigger the second path.
>! exec foo 2
>
># Running the command indirectly, via toolexec; trigger the third path.
>! go build -a -toolexec=foo runtime
