tests/run-tests.py: Detect threading and automatically run thread tests.

When detecting the target platform, also check if it has threading and
whether the GIL is enabled or not (using the new attribute
`sys.implementation._thread`).  If threading is available, add the thread
tests to the set of tests to run (unless the set of tests is explicitly
given).

With this change, the unix port no longer needs to explicitly run the set
of thread tests, so that line has been removed from the Makefile.

This change will make sure thread tests are run with other testing
combinations.  In particular, thread tests are now run:
- on the unix port with the native emitter
- on macOS builds
- on unix qemu, the architectures MIPS, ARM and RISCV-64

Signed-off-by: Damien George <damien@micropython.org>

ports/unix/Makefile

@@ -259,7 +259,6 @@ test: $(BUILD)/$(PROG) $(TOP)/tests/run-tests.py
 test_full_no_native: $(BUILD)/$(PROG) $(TOP)/tests/run-tests.py
 	$(eval DIRNAME=ports/$(notdir $(CURDIR)))
 	cd $(TOP)/tests && MICROPY_MICROPYTHON=../$(DIRNAME)/$(BUILD)/$(PROG) ./run-tests.py
-	cd $(TOP)/tests && MICROPY_MICROPYTHON=../$(DIRNAME)/$(BUILD)/$(PROG) ./run-tests.py -d thread
 	cd $(TOP)/tests && MICROPY_MICROPYTHON=../$(DIRNAME)/$(BUILD)/$(PROG) ./run-tests.py --via-mpy $(RUN_TESTS_MPY_CROSS_FLAGS) -d basics float micropython
 	cat $(TOP)/tests/basics/0prelim.py | ./$(BUILD)/$(PROG) | grep -q 'abc'
 

tests/feature_check/target_info.py

@@ -20,4 +20,6 @@ arch = [
     "xtensawin",
     "rv32imc",
 ][sys_mpy >> 10]
-print(platform, arch)
+thread = getattr(sys.implementation, "_thread", None)
+
+print(platform, arch, thread)

tests/run-tests.py

@@ -251,22 +251,27 @@ def detect_test_platform(pyb, args):
     output = run_feature_check(pyb, args, "target_info.py")
     if output.endswith(b"CRASH"):
         raise ValueError("cannot detect platform: {}".format(output))
-    platform, arch = str(output, "ascii").strip().split()
+    platform, arch, thread = str(output, "ascii").strip().split()
     if arch == "None":
         arch = None
     inlineasm_arch = detect_inline_asm_arch(pyb, args)
+    if thread == "None":
+        thread = None
 
     args.platform = platform
     args.arch = arch
     if arch and not args.mpy_cross_flags:
         args.mpy_cross_flags = "-march=" + arch
     args.inlineasm_arch = inlineasm_arch
+    args.thread = thread
 
     print("platform={}".format(platform), end="")
     if arch:
         print(" arch={}".format(arch), end="")
     if inlineasm_arch:
         print(" inlineasm={}".format(inlineasm_arch), end="")
+    if thread:
+        print(" thread={}".format(thread), end="")
     print()
 
 
@@ -810,8 +815,8 @@ def run_tests(pyb, tests, args, result_dir, num_threads=1):
         skip_tests.add("cmdline/repl_sys_ps1_ps2.py")
         skip_tests.add("extmod/ssl_poll.py")
 
-    # Skip thread mutation tests on targets that don't have the GIL.
-    if args.platform in PC_PLATFORMS + ("rp2",):
+    # Skip thread mutation tests on targets that have unsafe threading behaviour.
+    if args.thread == "unsafe":
         for t in tests:
             if t.startswith("thread/mutate_"):
                 skip_tests.add(t)
@@ -1329,6 +1334,8 @@ the last matching regex is used:
             )
             if args.inlineasm_arch is not None:
                 test_dirs += ("inlineasm/{}".format(args.inlineasm_arch),)
+            if args.thread is not None:
+                test_dirs += ("thread",)
             if args.platform == "pyboard":
                 # run pyboard tests
                 test_dirs += ("float", "stress", "ports/stm32")
@@ -1337,9 +1344,9 @@ the last matching regex is used:
             elif args.platform == "renesas-ra":
                 test_dirs += ("float", "ports/renesas-ra")
             elif args.platform == "rp2":
-                test_dirs += ("float", "stress", "thread", "ports/rp2")
+                test_dirs += ("float", "stress", "ports/rp2")
             elif args.platform == "esp32":
-                test_dirs += ("float", "stress", "thread")
+                test_dirs += ("float", "stress")
             elif args.platform in ("esp8266", "minimal", "samd", "nrf"):
                 test_dirs += ("float",)
             elif args.platform == "WiPy":