mtest: TestSetup can have [] as an exe_wrapper

Fix "meson test --wrapper foo --setup bar", it should work just fine
if the setup does not define a wrapper.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

mesonbuild/mtest.py

@@ -1490,10 +1490,10 @@ class TestHarness:
             options.timeout_multiplier = current.timeout_multiplier
     #    if options.env is None:
     #        options.env = current.env # FIXME, should probably merge options here.
-        if options.wrapper is not None and current.exe_wrapper is not None:
-            sys.exit('Conflict: both test setup and command line specify an exe wrapper.')
         if options.wrapper is None:
             options.wrapper = current.exe_wrapper
+        elif current.exe_wrapper:
+            sys.exit('Conflict: both test setup and command line specify an exe wrapper.')
         return current.env.get_env(os.environ.copy())
 
     def get_test_runner(self, test: TestSerialisation) -> SingleTestRunner:

run_unittests.py

@@ -2551,6 +2551,8 @@ class AllPlatformTests(BasePlatformTests):
         self._run(self.mtest_command + ['--setup=onlyenv3'])
         # Setup with only a timeout works
         self._run(self.mtest_command + ['--setup=timeout'])
+        # Setup that does not define a wrapper works with --wrapper
+        self._run(self.mtest_command + ['--setup=timeout', '--wrapper', shutil.which('valgrind')])
         # Setup that skips test works
         self._run(self.mtest_command + ['--setup=good'])
         with open(os.path.join(self.logdir, 'testlog-good.txt')) as f: