Add values to error messages

src/metpy/testing.py

@@ -53,20 +53,22 @@ def version_check(version_spec):
     module_name, comparison, version_number = _parse_version_spec(version_spec)
 
     # Check MetPy metadata for minimum required version of same package
-    _, _, minimum_version_number = _parse_version_spec(_get_metadata_spec(module_name))
+    metadata_spec = _get_metadata_spec(module_name)
+    _, _, minimum_version_number = _parse_version_spec(metadata_spec)
 
     installed_version = Version(version(module_name))
     specified_version = Version(version_number)
     minimum_version = Version(minimum_version_number)
 
     if specified_version < minimum_version:
-        raise ValueError('Specified package version older than MetPy minimum requirement.')
+        raise ValueError(
+            f'Specified {version_spec} outdated according to MetPy minimum {metadata_spec}.')
 
     try:
         return comparison_operators[comparison](installed_version, specified_version)
     except KeyError:
         raise ValueError(
-            "Comparison operator not one of ['==', '=', '!=', '<', '<=', '>', '>=']."
+            f'Comparison operator {comparison} not one of {list(comparison_operators)}.'
         ) from None
 
 

tests/test_testing.py

@@ -52,7 +52,7 @@ def test_module_version_check():
 
 def test_module_version_check_outdated_spec():
     """Test checking test version specs against package metadata."""
-    with pytest.raises(ValueError, match='Specified package version '):
+    with pytest.raises(ValueError, match='Specified numpy'):
         version_check('numpy>0.0.0')
 
 
@@ -64,5 +64,5 @@ def test_module_version_check_nonsense():
 
 def test_module_version_check_invalid_comparison():
     """Test invalid operator in version comparison."""
-    with pytest.raises(ValueError, match='Comparison operator not '):
+    with pytest.raises(ValueError, match='Comparison operator << '):
         version_check('numpy << 36')