From 3f8e5f109949dc6acb5fecd91c5067968fe271ee Mon Sep 17 00:00:00 2001
From: nanoric <nanoric@qq.com>
Date: Wed, 10 Oct 2018 22:26:17 -0400
Subject: [PATCH] =?UTF-8?q?[Add]=20Promise=E5=A2=9E=E5=8A=A0with=20self.ca?=
 =?UTF-8?q?tch():=E8=AF=AD=E6=B3=95=E6=94=AF=E6=8C=81?=
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---
 tests/Promise.py | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/tests/Promise.py b/tests/Promise.py
index d5fe4dfe..2e37d7f0 100644
--- a/tests/Promise.py
+++ b/tests/Promise.py
@@ -8,6 +8,7 @@ class PromiseResultType(Enum):
     Result = 1
     Exception = 2
     Traceback = 3
+    
 
 
 class Promise(object):
@@ -36,3 +37,23 @@ class Promise(object):
             self._queue.put((PromiseResultType.Exception, valueOrType))
         else:
             self._queue.put((PromiseResultType.Traceback, (valueOrType, val, tb)))
+
+    def catch(self):
+        """
+        Usage :
+        with promise.catch():
+            raise Exception();
+        """
+        return _PromiseCatchContext(self)
+
+
+class _PromiseCatchContext(object):
+    
+    def __init__(self, promise):
+        self.promise = promise
+    
+    def __enter__(self):
+        return self
+    
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.promise.set_exception(exc_type, exc_val, exc_tb)