Allow script-style ztests to run on Windows (#4581)

Script-style ztests require Bash on every OS and run with PATH set to
the equivalent of "$ZTEST_PATH:$PATH".  This is a change from the
previous value of "/bin:/usr/bin:$ZTEST_PATH".

ztest/shell.go

@@ -6,28 +6,23 @@ import (
 	"io"
 	"os"
 	"os/exec"
-	"runtime"
 )
 
 func RunShell(dir, bindir, script string, stdin io.Reader, useenvs []string) (string, string, error) {
-	var cmd *exec.Cmd
-	if runtime.GOOS == "windows" {
-		cmd = exec.Command("cmd.exe", "/c", script)
-	} else {
-		// "-e -o pipefile" ensures a test will fail if any command
-		// fails unexpectedly.
-		cmd = exec.Command("bash", "-e", "-o", "pipefail", "-c", script)
+	// "-e -o pipefile" ensures a test will fail if any command
+	// fails unexpectedly.
+	cmd := exec.Command("bash", "-e", "-o", "pipefail", "-c", script)
+	cmd.Dir = dir
+	cmd.Env = []string{
+		"AppData=" + dir, // For os.User*Dir on Windows.
+		"HOME=" + dir,    // For os.User*Dir on Unix.
+		"PATH=" + bindir + string(os.PathListSeparator) + os.Getenv("PATH"),
 	}
-
 	for _, env := range useenvs {
 		if v, ok := os.LookupEnv(env); ok {
 			cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", env, v))
 		}
 	}
-
-	cmd.Env = append(cmd.Env, "HOME="+dir)
-	cmd.Env = append(cmd.Env, "PATH=/bin:/usr/bin:"+bindir)
-	cmd.Dir = dir
 	cmd.Stdin = stdin
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout

ztest/ztest.go

@@ -129,7 +129,6 @@ import (
 	"os/exec"
 	"path/filepath"
 	"regexp"
-	"runtime"
 	"strings"
 	"testing"
 	"unicode/utf8"
@@ -329,11 +328,6 @@ func FromYAMLFile(filename string) (*ZTest, error) {
 
 func (z *ZTest) ShouldSkip(path string) string {
 	switch {
-	case z.Script != "" && runtime.GOOS == "windows":
-		// XXX skip in windows until we figure out the best
-		// way to support script-driven tests across
-		// environments
-		return "script test on Windows"
 	case z.Script != "" && path == "":
 		return "script test on in-process run"
 	case z.Skip != "":

ztest/ztest_test.go

@@ -3,27 +3,19 @@ package ztest
 import (
 	"os"
 	"path/filepath"
-	"runtime"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
 func TestShouldSkip(t *testing.T) {
-	if runtime.GOOS == "windows" {
-		assert.Equal(t, "script test on Windows", (&ZTest{Script: "x"}).ShouldSkip(""))
-	} else {
-		assert.Equal(t, "script test on in-process run", (&ZTest{Script: "x"}).ShouldSkip(""))
-	}
+	assert.Equal(t, "script test on in-process run", (&ZTest{Script: "x"}).ShouldSkip(""))
 	assert.Equal(t, "reason", (&ZTest{Skip: "reason"}).ShouldSkip(""))
 	assert.Equal(t, `tag "x" does not match ZTEST_TAG=""`, (&ZTest{Tag: "x"}).ShouldSkip(""))
 }
 
 func TestRunScript(t *testing.T) {
-	if runtime.GOOS == "windows" {
-		t.Skip("skipping test on Windows because RunScript uses cmd.exe instead of bash")
-	}
 	t.Run("outputs", func(t *testing.T) {
 		testDir := t.TempDir()
 		require.NoError(t, os.WriteFile(filepath.Join(testDir, "testdirfile"), []byte("testdirfile\n"), 0644))