Several minor fixes

.github/workflows/tests.yml

@@ -15,7 +15,7 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install Poetry
-        uses: snok/install-poetry@v1
+        run: pip install poetry
       - name: Install Dependencies
         run: poetry install
       - name: Run tests

runtype/base_types.py

@@ -15,7 +15,9 @@ class RuntypeError(TypeError):
 
 
 class TypeMismatchError(RuntypeError):
-    pass
+    def __str__(self) -> str:
+        v, t = self.args
+        return f"Expected type '{t}', but got value: {v}."
 
 
 

runtype/pytypes.py

@@ -56,7 +56,7 @@ class ProductType(base_types.ProductType, PythonType):
     """
     def validate_instance(self, obj, sampler=None):
         if not isinstance(obj, tuple):
-            raise TypeMismatchError(f"Expected a tuple. Got {type(obj)}")
+            raise TypeMismatchError(obj, tuple)
         if self.types and len(obj) != len(self.types):
             raise LengthMismatchError(self, obj)
         for type_, item in zip(self.types, obj):

runtype/validation.py

@@ -47,9 +47,9 @@ def assert_isa(obj, t):
             ensure_isa(obj, t)
         except TypeMismatchError as e:
             item_value, item_type = e.args
-            msg = f"Expected value of type {t}, instead got {obj!r}"
+            msg = f"Expected value of type '{t}', instead got '{obj!r}'."
             if item_value is not obj:
-                msg += f'\n\n    Failed on item: {item_value!r}, expected type {item_type}'
+                msg += f"\n\n    Failed on item: '{item_value!r}', expected type '{item_type}'."
             raise TypeError(msg)