misc/cgo/testtls: make test less flaky

Now it should always fail on ARM.
(The fix is on its way too.)

R=iant, r, dave
CC=golang-codereviews
https://golang.org/cl/55140043

diff --git a/misc/cgo/testtls/tls.go b/misc/cgo/testtls/tls.go
index a9546a61c23bd163f415ba1eb258245f104e0b39..8e9ee70033a4dc654e32ecd5b6d1d2d042b20219 100644 (file)
--- a/misc/cgo/testtls/tls.go
+++ b/misc/cgo/testtls/tls.go
@@ -15,14 +15,16 @@ import (
 )
 
 func testTLS(t *testing.T) {
-       var keyVal C.int = 1234
-
        runtime.LockOSThread()
        defer runtime.UnlockOSThread()
-       C.setTLS(C.int(keyVal))
-       storedVal := C.getTLS()
 
-       if storedVal != keyVal {
-               t.Fatalf("stored %d want %d", storedVal, keyVal)
+       if val := C.getTLS(); val != 0 {
+               t.Fatalf("at start, C.getTLS() = %#x, want 0", val)
+       }
+
+       const keyVal = 0x1234
+       C.setTLS(keyVal)
+       if val := C.getTLS(); val != keyVal {
+               t.Fatalf("at end, C.getTLS() = %#x, want %#x", val, keyVal)
        }
 }