fix: __version__ guard catches everything and leaves it unset on failure

Bare except: pass means any exception during the importlib.metadata
lookup gets silently swallowed (not just PackageNotFoundError for
"not installed"), and __version__ never gets set at all in that case --
spatialmath.__version__ raises AttributeError instead of giving
something to print. Narrow the except to PackageNotFoundError and
fall back to an explicit "unknown" so the attribute always exists.

Author: petercorke

spatialmath/__init__.py

@@ -51,5 +51,8 @@
     import importlib.metadata
 
     __version__ = importlib.metadata.version("spatialmath-python")
-except:
-    pass
+except importlib.metadata.PackageNotFoundError:
+    # running from a source checkout without an installed/editable
+    # spatialmath-python distribution -- e.g. importing straight from
+    # the repo root
+    __version__ = "unknown"

tests/test_version.py

@@ -0,0 +1,22 @@
+import re
+import unittest
+from pathlib import Path
+
+import spatialmath
+
+
+class TestVersion(unittest.TestCase):
+    def test_version_is_a_non_empty_string(self):
+        self.assertIsInstance(spatialmath.__version__, str)
+        self.assertTrue(spatialmath.__version__)
+
+    def test_version_matches_pyproject(self):
+        pyproject = Path(__file__).parent.parent / "pyproject.toml"
+        match = re.search(r'^version\s*=\s*"([^"]+)"', pyproject.read_text(), re.MULTILINE)
+        self.assertIsNotNone(match, f"couldn't find a version in {pyproject}")
+        self.assertEqual(spatialmath.__version__, match.group(1))
+
+
+# ---------------------------------------------------------------------------------------#
+if __name__ == "__main__":
+    unittest.main()