The trust is really more context than state, per review.

scenario/context.py

@@ -169,6 +169,7 @@ def __init__(
         capture_framework_events: bool = False,
         app_name: Optional[str] = None,
         unit_id: Optional[int] = 0,
+        app_trusted: bool = False,
     ):
         """Represents a simulated charm's execution context.
 
@@ -225,6 +226,8 @@ def __init__(
         :arg app_name: App name that this charm is deployed as. Defaults to the charm name as
             defined in metadata.yaml.
         :arg unit_id: Unit ID that this charm is deployed as. Defaults to 0.
+        :arg app_trusted: whether the charm has Juju trust (deployed with ``--trust`` or added with
+            ``juju trust``). Defaults to False
         :arg charm_root: virtual charm root the charm will be executed with.
             If the charm, say, expects a `./src/foo/bar.yaml` file present relative to the
             execution cwd, you need to use this. E.g.:
@@ -268,6 +271,7 @@ def __init__(
 
         self._app_name = app_name
         self._unit_id = unit_id
+        self.app_trusted = app_trusted
         self._tmp = tempfile.TemporaryDirectory()
 
         # config for what events to be captured in emitted_events.

scenario/mocking.py

@@ -632,9 +632,9 @@ def resource_get(self, resource_name: str) -> str:
             )
 
     def credential_get(self) -> CloudSpec:
-        if not self._state.trusted:
+        if not self._context.app_trusted:
             raise ModelError(
-                "ERROR charm is not trusted, initialise State with trusted=True",
+                "ERROR charm is not trusted, initialise Context with `app_trusted=True`",
             )
         if not self._state.model.cloud_spec:
             raise ModelError(

scenario/state.py

@@ -967,8 +967,6 @@ class State(_DCBase):
     """Whether this charm has leadership."""
     model: Model = Model()
     """The model this charm lives in."""
-    trusted: bool = False
-    """Whether ``juju-trust`` has been run for this charm."""
     secrets: List[Secret] = dataclasses.field(default_factory=list)
     """The secrets this charm has access to (as an owner, or as a grantee).
     The presence of a secret in this list entails that the charm can read it.

tests/test_e2e/test_cloud_spec.py

@@ -41,12 +41,11 @@ def test_get_cloud_spec():
             },
         ),
     )
-    ctx = scenario.Context(MyCharm, meta={"name": "foo"})
+    ctx = scenario.Context(MyCharm, meta={"name": "foo"}, app_trusted=True)
     state = scenario.State(
         model=scenario.Model(
             name="lxd-model", type="lxd", cloud_spec=scenario_cloud_spec
         ),
-        trusted=True,
     )
     with ctx.manager("start", state=state) as mgr:
         assert mgr.charm.model.get_cloud_spec() == expected_cloud_spec