Define and validate restored-session setup state

tests/session_contract.py

@@ -0,0 +1,24 @@
+"""Validate restored-session fixtures and rejection cases against Draft 2020-12."""
+
+import json
+from pathlib import Path
+
+from jsonschema import Draft202012Validator
+
+root = Path(__file__).resolve().parents[1]
+schema = json.loads((root / "contracts/v1/auth-session-response.json").read_text())
+Draft202012Validator.check_schema(schema)
+validator = Draft202012Validator(schema)
+
+for name in ["auth-session.authenticated.json", "auth-session.bootstrap.json"]:
+    validator.validate(json.loads((root / "fixtures/v1" / name).read_text()))
+
+for invalid in [
+    {"authenticated": True},
+    {"authenticated": False, "must_replace_credentials": False},
+    {"authenticated": True, "must_replace_credentials": "false"},
+    {"authenticated": True, "must_replace_credentials": False, "unexpected": True},
+]:
+    assert not validator.is_valid(invalid), "Invalid session response was accepted"
+
+print("Session schema: two valid fixtures and four rejection cases passed")