Issue #8513: os.get_exec_path() supports b'PATH' key and bytes value.
subprocess.Popen() and os._execvpe() support bytes program name. Add
os.supports_bytes_environ flag: True if the native OS type of the environment
is bytes (eg. False on Windows).
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index eb96706..96c8ebf 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -825,6 +825,27 @@
             stdout = stdout.rstrip(b'\n\r')
             self.assertEquals(stdout.decode('ascii'), repr(value))
 
+    def test_bytes_program(self):
+        abs_program = os.fsencode(sys.executable)
+        path, program = os.path.split(sys.executable)
+        program = os.fsencode(program)
+
+        # absolute bytes path
+        exitcode = subprocess.call([abs_program, "-c", "pass"])
+        self.assertEquals(exitcode, 0)
+
+        # bytes program, unicode PATH
+        env = os.environ.copy()
+        env["PATH"] = path
+        exitcode = subprocess.call([program, "-c", "pass"], env=env)
+        self.assertEquals(exitcode, 0)
+
+        # bytes program, bytes PATH
+        envb = os.environb.copy()
+        envb[b"PATH"] = os.fsencode(path)
+        exitcode = subprocess.call([program, "-c", "pass"], env=envb)
+        self.assertEquals(exitcode, 0)
+
 
 @unittest.skipUnless(mswindows, "Windows specific tests")
 class Win32ProcessTestCase(BaseTestCase):