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 "default - orc:test_accsadubl".

2 files changed, 13 insertions, 9 deletions

diff --git a/mesonbuild/mtest.py b/mesonbuild/mtest.py
index 337b70747..cdba8a60e 100644
--- a/mesonbuild/mtest.py
+++ b/mesonbuild/mtest.py
@@ -2073,14 +2073,18 @@ 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} - {name}'
+        return name
 
     def run_tests(self, runners: T.List[SingleTestRunner]) -> None:
         try:
diff --git a/unittests/allplatformstests.py b/unittests/allplatformstests.py
index 023b8c2ad..5e4739ce3 100644
--- a/unittests/allplatformstests.py
+++ b/unittests/allplatformstests.py
@@ -954,7 +954,7 @@ class AllPlatformTests(BasePlatformTests):
         self.utime(os.path.join(testdir, 'meson.build'))
         o = self._run(self.mtest_command + ['--list'])
         self.assertIn('Regenerating build files', o)
-        self.assertIn('test_features / xfail', o)
+        self.assertIn('test_features:xfail', o)
         o = self._run(self.mtest_command + ['--list'])
         self.assertNotIn('Regenerating build files', o)
         # no real targets should have been built
@@ -5437,7 +5437,7 @@ class AllPlatformTests(BasePlatformTests):
                                  '10/10': [10],
                                  }.items():
             output = self._run(self.mtest_command + ['--slice=' + arg])
-            tests = sorted([ int(x) for x in re.findall(r'\n[ 0-9]+/[0-9]+ test-([0-9]*)', output) ])
+            tests = sorted([ int(x) for x in re.findall(r'\n[ 0-9]+/[0-9]+ test_slice:test-([0-9]*)', output) ])
             self.assertEqual(tests, expectation)
 
         for arg, expectation in {'': 'error: argument --slice: value does not conform to format \'SLICE/NUM_SLICES\'',