exceptions: smarter, nicer exceptions from Failures

trezorlib/client.py

@@ -152,7 +152,7 @@ class BaseClient(object):
         if isinstance(resp, proto.Failure):
             if resp.code == proto.FailureType.ActionCancelled:
                 raise exceptions.Cancelled
-            raise exceptions.TrezorException(resp.code, resp.message)
+            raise exceptions.TrezorFailure(resp)
 
         return resp
 

trezorlib/exceptions.py

@@ -2,6 +2,26 @@ class TrezorException(Exception):
     pass
 
 
+class TrezorFailure(TrezorException):
+    def __init__(self, failure):
+        self.failure = failure
+        # TODO: this is backwards compatibility with tests. it should be changed
+        super().__init__(self.failure.code, self.failure.message)
+
+    def __str__(self):
+        from .messages import FailureType
+
+        types = {
+            getattr(FailureType, name): name
+            for name in dir(FailureType)
+            if not name.startswith("_")
+        }
+        if self.failure.message is not None:
+            return "{}: {}".format(types[self.failure.code], self.failure.message)
+        else:
+            return types[self.failure.code]
+
+
 class PinException(TrezorException):
     pass