Tests/python: check node connectivity (improvements)
When running a node with `Node.run`, it may take some time before the node is accepting RPC connections. Currenty, an arbitrary sleeping time is enforced in `sandbox.add_node` and in the tests that restart nodes. This may fail non-deterministically on some setups. This patch and the one before that add a new method to the client that polls a node using some RPC. `time.sleep` are replaced by a call to this method. This should make tests more robust and less dependent on the execution platform.
Showing with 19 additions and 10 deletions