singleflight: make the check for exec support in TestPanicDoChan plat…

…form-agnostic

The new wasip1 GOOS does not support exec, but some ios environments
(like Corellium) might. Update the test to exec itself with -test.list
as a control case.

For golang/go#58141.

Change-Id: Id69950fc394910620f6c73cb437ca75c09ad8c29
Reviewed-on: https://go-review.googlesource.com/c/sync/+/485980
Run-TryBot: Bryan Mills <[email protected]>
Commit-Queue: Bryan Mills <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Auto-Submit: Bryan Mills <[email protected]>
Reviewed-by: Johan Brandhorst-Satzkorn <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>

singleflight/singleflight_test.go

@@ -223,11 +223,24 @@ func TestGoexitDo(t *testing.T) {
  }
 }
 
-func TestPanicDoChan(t *testing.T) {
- if runtime.GOOS == "js" {
- t.Skipf("js does not support exec")
+func executable(t testing.TB) string {
+ exe, err := os.Executable()
+ if err != nil {
+ t.Skipf("skipping: test executable not found")
  }
 
+ // Control case: check whether exec.Command works at all.
+ // (For example, it might fail with a permission error on iOS.)
+ cmd := exec.Command(exe, "-test.list=^$")
+ cmd.Env = []string{}
+ if err := cmd.Run(); err != nil {
+ t.Skipf("skipping: exec appears not to work on %s: %v", runtime.GOOS, err)
+ }
+
+ return exe
+}
+
+func TestPanicDoChan(t *testing.T) {
  if os.Getenv("TEST_PANIC_DOCHAN") != "" {
  defer func() {
  recover()
@@ -243,7 +256,7 @@ func TestPanicDoChan(t *testing.T) {
 
  t.Parallel()
 
- cmd := exec.Command(os.Args[0], "-test.run="+t.Name(), "-test.v")
+ cmd := exec.Command(executable(t), "-test.run="+t.Name(), "-test.v")
  cmd.Env = append(os.Environ(), "TEST_PANIC_DOCHAN=1")
  out := new(bytes.Buffer)
  cmd.Stdout = out
@@ -266,10 +279,6 @@ func TestPanicDoChan(t *testing.T) {
 }
 
 func TestPanicDoSharedByDoChan(t *testing.T) {
- if runtime.GOOS == "js" {
- t.Skipf("js does not support exec")
- }
-
  if os.Getenv("TEST_PANIC_DOCHAN") != "" {
  blocked := make(chan struct{})
  unblock := make(chan struct{})
@@ -297,7 +306,7 @@ func TestPanicDoSharedByDoChan(t *testing.T) {
 
  t.Parallel()
 
- cmd := exec.Command(os.Args[0], "-test.run="+t.Name(), "-test.v")
+ cmd := exec.Command(executable(t), "-test.run="+t.Name(), "-test.v")
  cmd.Env = append(os.Environ(), "TEST_PANIC_DOCHAN=1")
  out := new(bytes.Buffer)
  cmd.Stdout = out