fix broken rebase things

Author: pipermerriam

populus/chain/__init__.py

@@ -1,9 +1,3 @@
-from populus.contracts.exceptions import (  # noqa: F401
-    NoKnownAddress,
-    UnknownContract,
-    BytecodeMismatch,
-)
-
 from .geth import (  # noqa: F401
     BaseGethChain,
     LocalGethChain,

populus/chain/base.py

@@ -61,11 +61,16 @@ def initialize_chain(self):
     #
     # Context manager API
     #
+    _running = None
+
     def __enter__(self):
-        raise NotImplementedError("Must be implemented by subclasses")
+        self._running = True
+        return self
 
     def __exit__(self, exc_type, exc_val, exc_tb):
-        pass
+        if not self._running:
+            raise ValueError("The TesterChain is not running")
+        self._running = False
 
     #
     # Chain Interaction API

populus/chain/tester.py

@@ -21,8 +21,3 @@ def __enter__(self):
         self.rpc_methods = self.web3.currentProvider.rpc_methods
 
         return self
-
-    def __exit__(self, *exc_info):
-        if not self._running:
-            raise ValueError("The TesterChain is not running")
-        self._running = False

populus/chain/testrpc.py

@@ -19,13 +19,11 @@ def get_web3_config(self):
         config['provider.settings.port'] = self.rpc_port
         return config
 
-    _running = None
-
     def __enter__(self):
         if self._running:
             raise ValueError("The TesterChain is already running")
 
-        if self.port is None:
+        if self.rpc_port is None:
             self.rpc_port = get_open_port()
 
         self._running = True