mtest: fix logic bug that broke tests where the cmd is a Windows found program

In this case, the test fname might have an implicit extension and cannot
be found by `os.path.isfile()`.

We cannot use `shutil.which()` to handle platform differences, because
not all test fnames are executable -- for example Java jars.

The test representation does have an "is built" attribute which in
theory should work here, because all built targets definitely have their
full filename known to Meson, but it turns out to be misnamed. Rename it
correctly and add an actual "is built" attribute to check.

Tests which aren't built by Meson can be assumed to exist without
consulting their existence on the filesystem.

Fixes #10027

1 files changed, 2 insertions, 0 deletions

diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index 6a78ed0..fbcb616 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -224,6 +224,7 @@ class TestSerialisation:
     protocol: TestProtocol
     priority: int
     cmd_is_built: bool
+    cmd_is_exe: bool
     depends: T.List[str]
     version: str
     verbose: bool
@@ -1147,6 +1148,7 @@ class Backend:
                                    t.is_parallel, cmd_args, t.env,
                                    t.should_fail, t.timeout, t.workdir,
                                    extra_paths, t.protocol, t.priority,
+                                   isinstance(exe, build.Target),
                                    isinstance(exe, build.Executable),
                                    [x.get_id() for x in depends],
                                    self.environment.coredata.version,