restructure test to check for errors

Signed-off-by: leongross <[email protected]>

src/os/os_chmod_test.go

@@ -33,75 +33,36 @@ func TestChmod(t *testing.T) {
 
 }
 
-func TestChown(t *testing.T) {
-	var (
-		TEST_UID_1           = 1001
-		TEST_GID_1           = 127
-		TEST_UID_2           = 0
-		TEST_GID_2           = 0
-		ERR_PERM_DENIED      = "permission denied"
-		ERR_OP_NOT_PERMITTED = "operation not permitted"
-	)
-
+// Since testing syscalls requires a static, predictable environment that has to be controlled
+// by the CI, we don't test for success but for failures and verify that the error messages are as expected.
+// EACCES is returned when the user does not have the required permissions to change the ownership of the file
+// ENOENT is returned when the file does not exist
+// ENOTDIR is returned when the file is not a directory
+func TestChownErr(t *testing.T) {
 	if runtime.GOOS == "windows" || runtime.GOOS == "plan9" {
-		t.Skip()
+		t.Skip("skipping on " + runtime.GOOS)
 	}
 
+	var (
+		TEST_UID_ROOT = 0
+		TEST_GID_ROOT = 0
+	)
+
 	f := newFile("TestChown", t)
 	defer Remove(f.Name())
 	defer f.Close()
 
-	// User with CI permissions run chown on owned file
-	// This test does not change the initial permissions of the file
-	// It only checks if the chown operation was successful and consistent
-	if err := Chown(f.Name(), TEST_UID_1, TEST_GID_1); err != nil {
-		if err.Error() != ERR_OP_NOT_PERMITTED {
-			t.Fatalf("chown(%s, uid=%v, gid=%v): got %v, want != nil", f.Name(), TEST_UID_1, TEST_GID_1, err)
+	// EACCES
+	if err := Chown(f.Name(), TEST_UID_ROOT, TEST_GID_ROOT); err != nil {
+		if err.(syscall.Errno) != syscall.EPERM {
+			t.Fatalf("chown(%s, uid=%v, gid=%v): got '%v', want %v", f.Name(), TEST_UID_ROOT, TEST_GID_ROOT, err, syscall.EPERM)
 		}
 	}
-	fi, err := Stat(f.Name())
-	if err != nil {
-		t.Fatalf("stat %s: got %v, want nil", f.Name(), err)
-	}
-
-	if fi.Sys() == nil {
-		t.Fatalf("stat %s: fi.Sys(): got nil", f.Name())
-	}
-
-	s, ok := fi.Sys().(*syscall.Stat_t)
-	if !ok {
-		t.Fatalf("stat %s: fi.Sys(): is not *syscall.Stat_t", f.Name())
-	}
-
-	uid, gid := s.Uid, s.Gid
-	if uid != uint32(TEST_UID_1) || gid != uint32(TEST_GID_1) {
-		t.Fatalf("chown(%s, %d, %d): want (%d,%d), got (%d, %d)", f.Name(), TEST_UID_1, TEST_GID_1, TEST_UID_1, TEST_GID_1, uid, gid)
-	}
-
-	// Root permission denied
-	if err = Chown(f.Name(), TEST_UID_2, TEST_GID_2); err.Error() != ERR_PERM_DENIED {
-		t.Fatalf("chown(%s, uid=%v, gid=%v): got %v, want != nil", f.Name(), TEST_UID_2, TEST_GID_2, err)
-	}
-
-	fi, err = Stat(f.Name())
-	if err != nil {
-		t.Fatalf("stat %s: got %v, want nil", f.Name(), err)
-	}
-
-	if fi.Sys() == nil {
-		t.Fatalf("stat %s: fi.Sys(): got nil", f.Name())
-	}
-
-	s, ok = fi.Sys().(*syscall.Stat_t)
-	if !ok {
-		t.Fatalf("stat %s: fi.Sys(): is not *syscall.Stat_t", f.Name())
-	}
 
-	uid, gid = s.Uid, s.Gid
-	if uid != uint32(TEST_UID_2) || gid != uint32(TEST_GID_2) {
-		// Chown will fail due to permissions denied, so the UID and GID should stay the same
-		if uid != uint32(TEST_UID_1) && gid != uint32(TEST_GID_1) {
-			t.Fatalf("chown(%s, %d, %d): want (%d,%d), got (%d, %d)", f.Name(), TEST_UID_2, TEST_GID_2, TEST_UID_2, TEST_GID_2, uid, gid)
+	// ENOENT
+	if err := Chown("invalid", Geteuid(), Getgid()); err != nil {
+		if err.(syscall.Errno) != syscall.ENOENT {
+			t.Fatalf("chown(%s, uid=%v, gid=%v): got '%v', want %v", f.Name(), Geteuid(), Getegid(), err, syscall.ENOENT)
 		}
 	}
 }