Pass message through to replaced exception

eth_utils/decorators.py

@@ -114,7 +114,7 @@ def wrapper(
                 return to_wrap(*args, **kwargs)
             except old_exceptions as err:
                 try:
-                    raise old_to_new_exceptions[type(err)] from err
+                    raise old_to_new_exceptions[type(err)](err) from err
                 except KeyError:
                     raise TypeError(
                         "could not look up new exception to use for %r" % err

newsfragments/198.bugfix.rst

@@ -0,0 +1 @@
+Pass context to new exception in ``replace_exceptions`` decorator.

tests/decorator-utils/test_replace_exceptions.py

@@ -7,7 +7,7 @@
 def mock_function_with_exception(old_to_new):
     @replace_exceptions(old_to_new)
     def function_with_exception(x):
-        raise TypeError
+        raise TypeError("Boom!")
 
     return function_with_exception
 
@@ -21,5 +21,5 @@ def function_with_exception(x):
     ),
 )
 def test_decorator_replaces_exceptions(mock_function_with_exception, old_to_new, new):
-    with pytest.raises(new):
+    with pytest.raises(new, match="Boom!"):
         mock_function_with_exception(old_to_new)