diff --git a/testing/src/scenario/mocking.py b/testing/src/scenario/mocking.py
index 754225715..903886069 100644
--- a/testing/src/scenario/mocking.py
+++ b/testing/src/scenario/mocking.py
@@ -33,6 +33,7 @@
     ModelError,
 )
 from ops._private.harness import ExecArgs, _TestingPebbleClient
+from ops.jujucontext import _JujuContext
 from ops.model import CloudSpec as CloudSpec_Ops
 from ops.model import Port as Port_Ops
 from ops.model import Secret as Secret_Ops  # lol
@@ -130,8 +131,9 @@ def __init__(
         event: "_Event",
         charm_spec: "_CharmSpec[CharmType]",
         context: "Context",
+        juju_context: "_JujuContext",
     ):
-        super().__init__()
+        super().__init__(juju_context=juju_context)
         self._state = state
         self._event = event
         self._context = context
diff --git a/testing/src/scenario/ops_main_mock.py b/testing/src/scenario/ops_main_mock.py
index 58bb1d05c..fbfea2909 100644
--- a/testing/src/scenario/ops_main_mock.py
+++ b/testing/src/scenario/ops_main_mock.py
@@ -30,17 +30,6 @@
 # pyright: reportPrivateUsage=false
 
 
-# TODO: Use ops.jujucontext's _JujuContext.charm_dir.
-def _get_charm_dir():
-    charm_dir = os.environ.get("JUJU_CHARM_DIR")
-    if charm_dir is None:
-        # Assume $JUJU_CHARM_DIR/lib/op/main.py structure.
-        charm_dir = pathlib.Path(f"{__file__}/../../..").resolve()
-    else:
-        charm_dir = pathlib.Path(charm_dir).resolve()
-    return charm_dir
-
-
 def _get_owner(root: Any, path: Sequence[str]) -> ops.ObjectEvents:
     """Walk path on root to an ObjectEvents instance."""
     obj = root
@@ -62,6 +51,7 @@ def _get_owner(root: Any, path: Sequence[str]) -> ops.ObjectEvents:
 def _emit_charm_event(
     charm: "CharmBase",
     event_name: str,
+    juju_context: ops.jujucontext._JujuContext,
     event: Optional["_Event"] = None,
 ):
     """Emits a charm event based on a Juju event name.
@@ -69,7 +59,8 @@ def _emit_charm_event(
     Args:
         charm: A charm instance to emit an event from.
         event_name: A Juju event name to emit on a charm.
-        event_owner_path: Event source lookup path.
+        event: Event to emit.
+        juju_context: Juju context to use for the event.
     """
     owner = _get_owner(charm, event.owner_path) if event else charm.on
 
@@ -82,11 +73,7 @@ def _emit_charm_event(
             f"invalid event (not on charm.on).",
         )
 
-    args, kwargs = _get_event_args(
-        charm,
-        event_to_emit,
-        ops.jujucontext._JujuContext.from_dict(os.environ),
-    )
+    args, kwargs = _get_event_args(charm, event_to_emit, juju_context)
     ops_logger.debug("Emitting Juju event %s.", event_name)
     event_to_emit.emit(*args, **kwargs)
 
@@ -97,17 +84,20 @@ def setup_framework(
     event: "_Event",
     context: "Context",
     charm_spec: "_CharmSpec[CharmType]",
+    juju_context: Optional[ops.jujucontext._JujuContext] = None,
 ):
     from .mocking import _MockModelBackend
 
+    if juju_context is None:
+        juju_context = ops.jujucontext._JujuContext.from_dict(os.environ)
     model_backend = _MockModelBackend(
         state=state,
         event=event,
         context=context,
         charm_spec=charm_spec,
+        juju_context=juju_context,
     )
-    debug = "JUJU_DEBUG" in os.environ
-    setup_root_logging(model_backend, debug=debug)
+    setup_root_logging(model_backend, debug=juju_context.debug)
     # ops sets sys.excepthook to go to Juju's debug-log, but that's not useful
     # in a testing context, so reset it.
     sys.excepthook = sys.__excepthook__
@@ -172,18 +162,20 @@ def setup(
     event: "_Event",
     context: "Context",
     charm_spec: "_CharmSpec[CharmType]",
+    juju_context: Optional[ops.jujucontext._JujuContext] = None,
 ):
     """Setup dispatcher, framework and charm objects."""
     charm_class = charm_spec.charm_type
-    charm_dir = _get_charm_dir()
+    if juju_context is None:
+        juju_context = ops.jujucontext._JujuContext.from_dict(os.environ)
+    charm_dir = juju_context.charm_dir
 
-    dispatcher = _Dispatcher(
-        charm_dir,
-        ops.jujucontext._JujuContext.from_dict(os.environ),
-    )
+    dispatcher = _Dispatcher(charm_dir, juju_context)
     dispatcher.run_any_legacy_hook()
 
-    framework = setup_framework(charm_dir, state, event, context, charm_spec)
+    framework = setup_framework(
+        charm_dir, state, event, context, charm_spec, juju_context
+    )
     charm = setup_charm(charm_class, framework, dispatcher)
     return dispatcher, framework, charm
 
@@ -197,11 +189,15 @@ def __init__(
         event: "_Event",
         context: "Context",
         charm_spec: "_CharmSpec[CharmType]",
+        juju_context: Optional[ops.jujucontext._JujuContext] = None,
     ):
         self.state = state
         self.event = event
         self.context = context
         self.charm_spec = charm_spec
+        if juju_context is None:
+            juju_context = ops.jujucontext._JujuContext.from_dict(os.environ)
+        self.juju_context = juju_context
 
         # set by setup()
         self.dispatcher: Optional[_Dispatcher] = None
@@ -220,6 +216,7 @@ def setup(self):
             self.event,
             self.context,
             self.charm_spec,
+            self.juju_context,
         )
 
     def emit(self):
@@ -236,7 +233,9 @@ def emit(self):
             if not dispatcher.is_restricted_context():
                 framework.reemit()
 
-            _emit_charm_event(charm, dispatcher.event_name, self.event)
+            _emit_charm_event(
+                charm, dispatcher.event_name, self.juju_context, self.event
+            )
 
         except Exception:
             framework.close()
diff --git a/testing/src/scenario/runtime.py b/testing/src/scenario/runtime.py
index 1206c119c..63a7d937a 100644
--- a/testing/src/scenario/runtime.py
+++ b/testing/src/scenario/runtime.py
@@ -5,7 +5,6 @@
 import copy
 import dataclasses
 import marshal
-import os
 import re
 import tempfile
 import typing
@@ -35,6 +34,7 @@
     NoTypeError,
     PreCommitEvent,
 )
+from ops.jujucontext import _JujuContext
 from ops.storage import NoSnapshotError, SQLiteStorage
 from ops.framework import _event_regex
 from ops._private.harness import ActionFailed
@@ -183,15 +183,6 @@ def __init__(
         self._app_name = app_name
         self._unit_id = unit_id
 
-    @staticmethod
-    def _cleanup_env(env: Dict[str, str]):
-        # TODO consider cleaning up env on __delete__, but ideally you should be
-        #  running this in a clean env or a container anyway.
-        # cleanup the env, in case we'll be firing multiple events, we don't want to pollute it.
-        for key in env:
-            # os.unsetenv does not always seem to work !?
-            del os.environ[key]
-
     def _get_event_env(self, state: "State", event: "_Event", charm_root: Path):
         """Build the simulated environment the operator framework expects."""
         env = {
@@ -430,7 +421,7 @@ def exec(
         Returns the 'output state', that is, the state as mutated by the charm during the
         event handling.
 
-        This will set the environment up and call ops.main.main().
+        This will set the environment up and call ops.main().
         After that it's up to ops.
         """
         # todo consider forking out a real subprocess and do the mocking by
@@ -457,7 +448,7 @@ def exec(
                 event=event,
                 charm_root=temporary_charm_root,
             )
-            os.environ.update(env)
+            juju_context = _JujuContext.from_dict(env)
 
             logger.info(" - Entering ops.main (mocked).")
             from .ops_main_mock import Ops  # noqa: F811
@@ -471,6 +462,7 @@ def exec(
                         self._charm_spec,
                         charm_type=self._wrap(charm_type),
                     ),
+                    juju_context=juju_context,
                 )
                 ops.setup()
 
@@ -489,9 +481,6 @@ def exec(
             finally:
                 logger.info(" - Exited ops.main.")
 
-                logger.info(" - Clearing env")
-                self._cleanup_env(env)
-
             logger.info(" - closing storage")
             output_state = self._close_storage(output_state, temporary_charm_root)
 
diff --git a/testing/tests/test_runtime.py b/testing/tests/test_runtime.py
index 11c46035e..b303fadf8 100644
--- a/testing/tests/test_runtime.py
+++ b/testing/tests/test_runtime.py
@@ -85,11 +85,11 @@ def test_unit_name(app_name, unit_id):
         state=State(),
         event=_Event("start"),
         context=Context(my_charm_type, meta=meta),
-    ) as ops:
-        assert ops.charm.unit.name == f"{app_name}/{unit_id}"
+    ) as manager:
+        assert manager.charm.unit.name == f"{app_name}/{unit_id}"
 
 
-def test_env_cleanup_on_charm_error():
+def test_env_clean_on_charm_error():
     meta = {"name": "frank", "requires": {"box": {"interface": "triangle"}}}
 
     my_charm_type = charm_type()
@@ -101,14 +101,19 @@ def test_env_cleanup_on_charm_error():
         ),
     )
 
-    rel = Relation("box")
-    with pytest.raises(UncaughtCharmError):
+    remote_name = "ava"
+    rel = Relation("box", remote_app_name=remote_name)
+    with pytest.raises(UncaughtCharmError) as exc:
         with runtime.exec(
             state=State(relations={rel}),
             event=_Event("box_relation_changed", relation=rel),
             context=Context(my_charm_type, meta=meta),
-        ):
-            assert os.getenv("JUJU_REMOTE_APP")
+        ) as manager:
+            assert manager.juju_context.remote_app_name == remote_name
+            assert "JUJU_REMOTE_APP" not in os.environ
             _ = 1 / 0  # raise some error
+    # Ensure that some other error didn't occur (like AssertionError!).
+    assert "ZeroDivisionError" in str(exc.value)
 
+    # Ensure that the Juju environment didn't leak into the outside one.
     assert os.getenv("JUJU_REMOTE_APP", None) is None