tests/bytes_compare: Rework test for bytes <-> str comparison.

This may produce a warning, depending on MicroPython configuration.

tests/basics/bytes_compare2.py

@@ -1,6 +1,5 @@
 print(b"1" == 1)
 print(b"123" == bytearray(b"123"))
-print(b"123" == "123")
 print(b'123' < bytearray(b"124"))
 print(b'123' > bytearray(b"122"))
 print(bytearray(b"23") in b"1234")

tests/basics/bytes_compare3.py

@@ -0,0 +1,9 @@
+# Based on MicroPython config option, comparison of str and bytes
+# or vice versa may issue a runtime warning. On CPython, if run as
+# "python3 -b", only comparison of str to bytes issues a warning,
+# not the other way around (while exactly comparison of bytes to
+# str would be the most common error, as in sock.recv(3) == "GET").
+# Update: the issue above with CPython apparently happens in REPL,
+# when run as a script, both lines issue a warning.
+print("123" == b"123")
+print(b"123" == "123")

tests/basics/bytes_compare3.py.exp

@@ -0,0 +1,4 @@
+########
+False
+########
+False

tests/run-tests

@@ -27,9 +27,10 @@ def rm_f(fname):
         os.remove(fname)
 
 def run_micropython(pyb, args, test_file):
+    special_tests = ('micropython/meminfo.py', 'basics/bytes_compare3.py')
     if pyb is None:
         # run on PC
-        if test_file.startswith(('cmdline/', 'feature_check/')) or test_file == 'micropython/meminfo.py':
+        if test_file.startswith(('cmdline/', 'feature_check/')) or test_file in special_tests :
             # special handling for tests of the unix cmdline program
 
             # check for any cmdline options needed for this test