The newly added `client.getContext()` produces something that should be passable to any remote method as the last argument. It's not always needed for every method, only when performing a query, but usually safest to put it in more often that not. An alternative is to do what `test_permissions.py` does and set the context on the proxy itself. E.g.:
```
    def testOGSetProxyContext(self):
        # """ test omero.group can be set on a proxy """

        class F(CallContextFixture):
            def query_service(this):
                service = this.sf.getQueryService()
                ctx = this.client.ic.getImplicitContext().getContext()  # This is now `client.getContext()`
                ctx["omero.group"] = "-1"
                return service.ice_context(ctx)
        F(self).assertCallContext()
```