mtest: Display test name in format expected by "meson test" argument

This makes easier to run a single test after running them all. For
example the test "test_accsadubl" in the suite "default" of project
"orc" used to be displayed "orc:default / test_accsadubl". To run that
test specifically the command line is `meson test -C builddir
orc:test_accsadubl --suite default`. To make this more consistent
the test is now displayed as "orc:test_accsadubl (default)".

Fix tests having no suite in the case `suite: []` is passed. Empty list
is now converted to `['']` which was the default value of that kwarg.

mesonbuild/interpreter/type_checking.py

@@ -484,6 +484,14 @@ VARIABLES_KW: KwargInfo[T.Dict[str, str]] = KwargInfo(
 
 PRESERVE_PATH_KW: KwargInfo[bool] = KwargInfo('preserve_path', bool, default=False, since='0.63.0')
 
+
+def suite_convertor(suite: T.List[str]) -> T.List[str]:
+    # Ensure we always have at least one suite, it will be set to project name.
+    if not suite:
+        return ['']
+    return suite
+
+
 TEST_KWS: T.List[KwargInfo] = [
     KwargInfo('args', ContainerTypeInfo(list, (str, File, BuildTarget, CustomTarget, CustomTargetIndex)),
               listify=True, default=[]),
@@ -499,7 +507,7 @@ TEST_KWS: T.List[KwargInfo] = [
     # TODO: env needs reworks of the way the environment variable holder itself works probably
     ENV_KW,
     DEPENDS_KW.evolve(since='0.46.0'),
-    KwargInfo('suite', ContainerTypeInfo(list, str), listify=True, default=['']),  # yes, a list of empty string
+    KwargInfo('suite', ContainerTypeInfo(list, str), listify=True, default=[], convertor=suite_convertor),
     KwargInfo('verbose', bool, default=False, since='0.62.0'),
 ]
 

mesonbuild/mtest.py

@@ -1980,14 +1980,18 @@ class TestHarness:
         return wrap
 
     def get_pretty_suite(self, test: TestSerialisation) -> str:
-        if len(self.suites) > 1 and test.suite:
-            rv = TestHarness.split_suite_string(test.suite[0])[0]
-            s = "+".join(TestHarness.split_suite_string(s)[1] for s in test.suite)
+        assert test.suite, 'Interpreter should ensure there is always at least one suite'
+        prj = TestHarness.split_suite_string(test.suite[0])[0]
+        suites: T.List[str] = []
+        for i in test.suite:
+            s = TestHarness.split_suite_string(i)[1]
             if s:
-                rv += ":"
-            return rv + s + " / " + test.name
-        else:
-            return test.name
+                suites.append(s)
+        name = f'{prj}:{test.name}'
+        if suites:
+            s = ', '.join(suites)
+            name += f' ({s})'
+        return name
 
     def run_tests(self, runners: T.List[SingleTestRunner]) -> None:
         try: