feat(lnprototest): Add stash function to the connection

This commit introduce the ability to stash information inside
the connection.

This function allow lnprototest to build connection that can
keep state by connection.

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

lnprototest/dummyrunner.py

@@ -1,18 +1,19 @@
-#! /usr/bin/python3
 # #### Dummy runner which you should replace with real one. ####
 import io
-from .runner import Runner, Conn
-from .event import Event, ExpectMsg, MustNotMsg
-from typing import List, Optional
-from .keyset import KeySet
+from typing import Any
+
 from pyln.proto.message import (
     Message,
     FieldType,
     DynamicArrayType,
     EllipsisArrayType,
     SizedArrayType,
 )
-from typing import Any
+
+from .runner import Runner, Conn
+from .event import Event, ExpectMsg, MustNotMsg
+from typing import List, Optional
+from .keyset import KeySet
 
 
 class DummyRunner(Runner):

lnprototest/runner.py

@@ -39,8 +39,13 @@ def __str__(self) -> str:
 
 
 class RunnerConn(Conn):
-    """Default Connection implementation for a runner that use the pyln.proto
-    to open a connection over a socket."""
+    """
+    Default Connection implementation for a runner that use the pyln.proto
+    to open a connection over a socket.
+
+    Each connection has an internal memory to stash information
+    and keep connection state.
+    """
 
     def __init__(
         self,
@@ -58,6 +63,20 @@ def __init__(
             host,
             port,
         )
+        self.stash: Dict[str, Dict[str, Any]] = {}
+        self.logger = logging.getLogger(__name__)
+
+    def add_stash(self, stashname: str, vals: Any) -> None:
+        """Add a dict to the stash."""
+        self.stash[stashname] = vals
+
+    def get_stash(self, event: Event, stashname: str, default: Any = None) -> Any:
+        """Get an entry from the stash."""
+        if stashname not in self.stash:
+            if default is not None:
+                return default
+            raise SpecFileError(event, "Unknown stash name {}".format(stashname))
+        return self.stash[stashname]
 
 
 class Runner(ABC):