Issue #8513: On UNIX, subprocess supports bytes command string.
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 9e267eb..d91a4a6 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -1059,6 +1059,11 @@
         exitcode = subprocess.call([abs_program, "-c", "pass"])
         self.assertEqual(exitcode, 0)
 
+        # absolute bytes path as a string
+        cmd = b"'" + abs_program + b"' -c pass"
+        exitcode = subprocess.call(cmd, shell=True)
+        self.assertEqual(exitcode, 0)
+
         # bytes program, unicode PATH
         env = os.environ.copy()
         env["PATH"] = path