Test FastlyPlatformSecretStore read path and write stubs (PR4)

crates/trusted-server-adapter-fastly/src/platform.rs

@@ -534,6 +534,47 @@ mod tests {
         );
     }
 
+    #[test]
+    fn get_secret_bytes_returns_error_when_open_fails() {
+        let err = get_secret_bytes::<StubSecretStore, _, _>("signing_keys", "active", || {
+            Err::<StubSecretStore, &'static str>("permission denied")
+        })
+        .expect_err("should return an error when the secret store cannot be opened");
+
+        assert!(
+            matches!(err.current_context(), &PlatformError::SecretStore),
+            "should surface as PlatformError::SecretStore"
+        );
+    }
+
+    // --- FastlyPlatformSecretStore write stubs ------------------------------
+
+    #[test]
+    fn fastly_platform_secret_store_create_returns_not_implemented() {
+        let store = FastlyPlatformSecretStore;
+        let err = store
+            .create(&StoreId::from("test-store-id"), "my-secret", "value")
+            .expect_err("should return an error for unimplemented create");
+
+        assert!(
+            matches!(err.current_context(), &PlatformError::NotImplemented),
+            "should report NotImplemented while secret store write is not yet implemented"
+        );
+    }
+
+    #[test]
+    fn fastly_platform_secret_store_delete_returns_not_implemented() {
+        let store = FastlyPlatformSecretStore;
+        let err = store
+            .delete(&StoreId::from("test-store-id"), "my-secret")
+            .expect_err("should return an error for unimplemented delete");
+
+        assert!(
+            matches!(err.current_context(), &PlatformError::NotImplemented),
+            "should report NotImplemented while secret store write is not yet implemented"
+        );
+    }
+
     #[test]
     fn fastly_platform_http_client_reports_not_implemented() {
         let client = FastlyPlatformHttpClient;