refactor: enforce frontend view model boundaries

src/features/tbank-connection/model/screen-sync.test.tsx

@@ -19,11 +19,14 @@ function auth() {
 		refresh: () => Promise.resolve(true),
 	});
 }
+
 describe("page-owned screen synchronization", () => {
 	it("ignores a late sync acceptance after the account scope changes", async () => {
 		auth();
 
-		const { promise: blocked, resolve: release } = Promise.withResolvers<void>();
+		const { promise: blocked, resolve: release }
+			= Promise.withResolvers<void>();
+
 		const posted: string[] = [];
 		const polled: string[] = [];
 		server.use(
@@ -32,8 +35,10 @@ describe("page-owned screen synchronization", () => {
 					accountId: string;
 					screen: "account";
 				};
+
 				posted.push(scope.accountId);
 				await blocked;
+
 				return HttpResponse.json(
 					{ id: scope.accountId, now: "2026-09-25T00:00:00Z", scope },
 					{ status: 202 },
@@ -41,6 +46,7 @@ describe("page-owned screen synchronization", () => {
 			}),
 			http.get("*/api/v1/tbank-sync/:id", ({ params }) => {
 				polled.push(String(params.id));
+
 				return HttpResponse.json({
 					id: params.id,
 					resources: [],
@@ -48,6 +54,7 @@ describe("page-owned screen synchronization", () => {
 				});
 			}),
 		);
+
 		const { rerender, result } = renderHook(
 			({ accountId }) => useScreenSync({ accountId, screen: "account" }, []),
 			{
@@ -55,6 +62,7 @@ describe("page-owned screen synchronization", () => {
 				wrapper: createQueryWrapper().wrapper,
 			},
 		);
+
 		let pending!: Promise<void>;
 		act(() => {
 			pending = result.current.refresh();
@@ -79,6 +87,7 @@ describe("page-owned screen synchronization", () => {
 			server.use(
 				http.get("*/api/v1/brokerage-accounts", ({ request }) => {
 					modes.push(new URL(request.url).searchParams.get("sync"));
+
 					return isUnavailable
 						? HttpResponse.json({ code: "UNAVAILABLE" }, { status: 503 })
 						: HttpResponse.json(
@@ -87,14 +96,17 @@ describe("page-owned screen synchronization", () => {
 				}),
 				http.post("*/api/v1/tbank-sync", () => {
 					posts += 1;
+
 					return new HttpResponse(null, { status: 500 });
 				}),
 			);
 			const { queryClient, wrapper } = createQueryWrapper();
+
 			const { result } = renderHook(
 				() => {
 					const accounts = useBrokerageAccounts();
 					const disabled = useStockQuote("");
+
 					return {
 						accounts,
 						disabled,
@@ -103,6 +115,7 @@ describe("page-owned screen synchronization", () => {
 				},
 				{ wrapper },
 			);
+
 			if (cached) {
 				await waitFor(() =>
 					// eslint-disable-next-line vitest/no-conditional-expect -- The fixed table case selects the expected outcome; every case asserts its own branch.
@@ -111,6 +124,7 @@ describe("page-owned screen synchronization", () => {
 				isUnavailable = true;
 				await act(() => result.current.accounts.refetch());
 			}
+
 			await waitFor(() => expect(result.current.accounts.isError).toBe(true));
 			isUnavailable = false;
 			await act(() => result.current.sync.retry());
@@ -119,7 +133,14 @@ describe("page-owned screen synchronization", () => {
 				cached ? "3" : "2",
 			);
 			expect(modes).toEqual(
-				cached ? [null, /* eslint-disable-line unicorn/no-null -- Exercise the explicit null returned by the production API/DOM contract. */ null, "observe"] : [null, "observe"],
+				cached
+					? [
+							null, // eslint-disable-line unicorn/no-null -- Preserve explicit null in the API fixture.
+							// eslint-disable-next-line unicorn/no-null -- Exercise the explicit null returned by the production API/DOM contract.
+							null,
+							"observe",
+						]
+					: [null, "observe"], // eslint-disable-line unicorn/no-null -- Preserve explicit null in the API fixture.
 			);
 			expect(posts).toBe(0);
 			expect(result.current.disabled.data).toBeUndefined();
@@ -141,7 +162,9 @@ describe("page-owned screen synchronization", () => {
 		async (boundary, pending) => {
 			auth();
 
-			const { promise: blocked, resolve: release } = Promise.withResolvers<void>();
+			const { promise: blocked, resolve: release }
+				= Promise.withResolvers<void>();
+
 			let isRecovering = false;
 			let isChanged = false;
 			server.use(
@@ -154,18 +177,22 @@ describe("page-owned screen synchronization", () => {
 							: HttpResponse.json({ code: "UNAVAILABLE" }, { status: 503 });
 					isRecovering = true;
 					await blocked;
+
 					return HttpResponse.json(resource([], { stateVersion: "old" }));
 				}),
 			);
 			const { queryClient, wrapper } = createQueryWrapper();
 			const published: unknown[] = [];
+
 			const unsubscribe = queryClient.getQueryCache().subscribe((event) => {
 				if (event.type === "updated" && event.action.type === "success")
 					published.push(event.query.state.data);
 			});
+
 			const { result } = renderHook(
 				() => {
 					const accounts = useBrokerageAccounts();
+
 					return {
 						accounts,
 						sync: useScreenSync({ screen: "accounts" }, [accounts]),
@@ -173,6 +200,7 @@ describe("page-owned screen synchronization", () => {
 				},
 				{ wrapper },
 			);
+
 			await waitFor(() => expect(result.current.accounts.isError).toBe(true));
 			let recovery!: Promise<void>;
 			act(() => {
@@ -182,6 +210,7 @@ describe("page-owned screen synchronization", () => {
 			if (pending) await waitFor(() => expect(isRecovering).toBe(true));
 			await act(async () => {
 				isChanged = true;
+
 				switch (boundary) {
 					case "access": {
 						invalidateResourceAccess(queryClient, "brokerage", {
@@ -190,24 +219,29 @@ describe("page-owned screen synchronization", () => {
 
 						break;
 					}
+
 					case "logout": {
 						configureAuthClient();
 						queryClient.clear();
 
 						break;
 					}
+
 					case "session": {
 						auth();
 						queryClient.clear();
 
 						break;
 					}
-					case "connection": { commitTbankConnectionBoundary(queryClient, {
-						connected: true,
-						connectedAt: "2026-09-27T00:00:00Z",
-					});
+
+					case "connection": {
+						commitTbankConnectionBoundary(queryClient, {
+							connected: true,
+							connectedAt: "2026-09-27T00:00:00Z",
+						});
 					}
 				}
+
 				release();
 				await recovery;
 			});
@@ -233,6 +267,7 @@ describe("page-owned screen synchronization", () => {
 			server.use(
 				http.get("*/api/v1/brokerage-accounts", ({ request }) => {
 					modes.push(new URL(request.url).searchParams.get("sync"));
+
 					return modes.length === 1
 						? HttpResponse.json({ code: "UNAVAILABLE" }, { status: 503 })
 						: HttpResponse.json(resource([]));
@@ -242,6 +277,7 @@ describe("page-owned screen synchronization", () => {
 				),
 				http.get("*/api/v1/tbank-sync/:id", () => {
 					polls += 1;
+
 					return retryStatus && polls === 1
 						? HttpResponse.json({ code: "UNAVAILABLE" }, { status: 503 })
 						: HttpResponse.json({
@@ -252,10 +288,12 @@ describe("page-owned screen synchronization", () => {
 				}),
 			);
 			const { queryClient, wrapper } = createQueryWrapper();
+
 			const { result } = renderHook(
 				() => {
 					const accounts = useBrokerageAccounts();
 					const disabled = useStockQuote("");
+
 					return {
 						accounts,
 						sync: useScreenSync({ screen: "accounts" }, [accounts, disabled]),
@@ -263,9 +301,11 @@ describe("page-owned screen synchronization", () => {
 				},
 				{ wrapper },
 			);
+
 			await waitFor(() => expect(result.current.accounts.isError).toBe(true));
 			expect(result.current.accounts.meta).toBeUndefined();
 			await act(() => result.current.sync.refresh());
+
 			if (retryStatus) {
 				await waitFor(() =>
 					// eslint-disable-next-line vitest/no-conditional-expect -- The fixed table case selects the expected outcome; every case asserts its own branch.
@@ -273,6 +313,7 @@ describe("page-owned screen synchronization", () => {
 				);
 				await act(() => result.current.sync.retry());
 			}
+
 			await waitFor(() => expect(result.current.accounts.isSuccess).toBe(true));
 			expect(result.current.accounts.data).toEqual([]);
 			// eslint-disable-next-line unicorn/no-null -- Preserve the API/DOM null sentinel in the expected response.
@@ -290,16 +331,20 @@ describe("page-owned screen synchronization", () => {
 		const bodies: unknown[] = [];
 		let isCompleted = false;
 		let polls = 0;
+
 		const meta = () =>
 			resource([], { stateVersion: isCompleted ? "2" : "1" }).meta;
+
 		server.use(
 			http.get("*/api/v1/brokerage-accounts", ({ request }) => {
 				modes.push(new URL(request.url).searchParams.get("sync"));
+
 				return HttpResponse.json(resource([], meta()));
 			}),
 			http.post("*/api/v1/tbank-sync", async ({ request }) => {
 				bodies.push(await request.json());
 				isCompleted = true;
+
 				return HttpResponse.json(
 					{
 						id: "screen",
@@ -311,7 +356,10 @@ describe("page-owned screen synchronization", () => {
 			}),
 			http.get("*/api/v1/tbank-sync/:id", () => {
 				polls++;
-				return HttpResponse.json((/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+
+				/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+
+				return HttpResponse.json(
 					{
 						errorCode: null,
 						id: "screen",
@@ -320,13 +368,16 @@ describe("page-owned screen synchronization", () => {
 						resources: [meta()],
 						scope: { screen: "accounts" },
 						state: "succeeded",
-					}
-					/* eslint-enable unicorn/no-null */));
+					},
+					/* eslint-enable unicorn/no-null */
+				);
 			}),
 		);
+
 		const { result, unmount } = renderHook(
 			() => {
 				const accounts = useBrokerageAccounts();
+
 				return {
 					accounts,
 					sync: useScreenSync({ screen: "accounts" }, [accounts]),
@@ -334,6 +385,7 @@ describe("page-owned screen synchronization", () => {
 			},
 			{ wrapper: createQueryWrapper().wrapper },
 		);
+
 		await waitFor(() => expect(result.current.accounts.data).toEqual([]));
 		await act(async () => {
 			await Promise.all([
@@ -348,6 +400,7 @@ describe("page-owned screen synchronization", () => {
 		// eslint-disable-next-line unicorn/no-null -- Preserve the API/DOM null sentinel in the expected response.
 		expect(modes).toEqual([null, "observe"]);
 		vi.useFakeTimers();
+
 		try {
 			await act(() => vi.advanceTimersByTimeAsync(120_000));
 			expect(polls).toBe(1);
@@ -365,26 +418,36 @@ describe("page-owned screen synchronization", () => {
 		"publishes completed empty coverage while history runs, then stops on %s",
 		async (boundary) => {
 			vi.useFakeTimers({ toFake: ["Date"] });
+
 			try {
 				auth();
 				let isCompleted = false;
 				let polls = 0;
 				const modes: (null | string)[] = [];
+
 				const snapshot = () =>
-					resource(isCompleted ? [] : /* eslint-disable-line unicorn/no-null -- Exercise the explicit null returned by the production API/DOM contract. */ null, (/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+					resource(
+						isCompleted
+							? []
+							: null, // eslint-disable-line unicorn/no-null -- Preserve the nullable API fixture.
 						{
 							stateVersion: isCompleted ? "covered" : "initial",
-							sync: { errorCode: null, id: "history", state: "running" },
-						}
-						/* eslint-enable unicorn/no-null */));
+							sync: { errorCode: null, id: "history", state: "running" }, // eslint-disable-line unicorn/no-null -- Preserve explicit null in the API fixture.
+						},
+					);
+
 				server.use(
 					http.get("*/api/v1/brokerage-accounts", ({ request }) => {
 						modes.push(new URL(request.url).searchParams.get("sync"));
+
 						return HttpResponse.json(snapshot());
 					}),
 					http.get("*/api/v1/tbank-sync/:id", () => {
 						polls++;
-						return HttpResponse.json((/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+
+						/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+
+						return HttpResponse.json(
 							{
 								errorCode: null,
 								id: "history",
@@ -397,13 +460,16 @@ describe("page-owned screen synchronization", () => {
 								resources: [snapshot().meta],
 								scope: null,
 								state: "running",
-							}
-							/* eslint-enable unicorn/no-null */));
+							},
+							/* eslint-enable unicorn/no-null */
+						);
 					}),
 				);
+
 				const { result, unmount } = renderHook(
 					() => {
 						const accounts = useBrokerageAccounts();
+
 						return {
 							accounts,
 							sync: useScreenSync({ screen: "accounts" }, [accounts]),
@@ -411,6 +477,7 @@ describe("page-owned screen synchronization", () => {
 					},
 					{ wrapper: createQueryWrapper().wrapper },
 				);
+
 				await waitFor(() =>
 					expect(result.current.accounts.meta?.sync.id).toBe("history"),
 				);
@@ -447,20 +514,25 @@ describe("page-owned screen synchronization", () => {
 		server.use(
 			http.get("*/api/v1/brokerage-accounts", () =>
 				HttpResponse.json(
-					resource([], (/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+					resource(
+						/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+						[],
 						{
 							sync: { errorCode: null, id: "revoked", state: "running" },
-						}
-						/* eslint-enable unicorn/no-null */)),
+						},
+						/* eslint-enable unicorn/no-null */
+					),
 				),
 			),
 			http.get("*/api/v1/tbank-sync/:id", () =>
 				HttpResponse.json({ code: "INVALID_TBANK_TOKEN" }, { status: 400 }),
 			),
 		);
+
 		const { result } = renderHook(
 			() => {
 				const accounts = useBrokerageAccounts();
+
 				return {
 					accounts,
 					sync: useScreenSync({ screen: "accounts" }, [accounts]),
@@ -468,6 +540,7 @@ describe("page-owned screen synchronization", () => {
 			},
 			{ wrapper: createQueryWrapper().wrapper },
 		);
+
 		await waitFor(() => expect(result.current.accounts.isError).toBe(true));
 		expect(result.current.accounts.data).toBeUndefined();
 	});
@@ -475,7 +548,10 @@ describe("page-owned screen synchronization", () => {
 		auth();
 		let isObserved = false;
 		const modes: (null | string)[] = [];
-		const dependency = resource([], (/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+
+		const dependency = resource(
+			/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+			[],
 			{
 				resourceKey: "operations",
 				stateVersion: isObserved ? "covered" : "initial",
@@ -484,24 +560,36 @@ describe("page-owned screen synchronization", () => {
 					id: "dependency",
 					state: isObserved ? "idle" : "running",
 				},
-			}
-			/* eslint-enable unicorn/no-null */)).meta;
+			},
+			/* eslint-enable unicorn/no-null */
+		).meta;
+
 		server.use(
 			http.get("*/api/v1/brokerage-accounts", ({ request }) => {
 				const mode = new URL(request.url).searchParams.get("sync");
 				modes.push(mode);
 				if (mode) isObserved = true;
+
 				return HttpResponse.json(
-					resource(isObserved ? [] : /* eslint-disable-line unicorn/no-null -- Exercise the explicit null returned by the production API/DOM contract. */ null, {
-						dependencies: [
-							{ ...dependency, stateVersion: isObserved ? "covered" : "initial" },
-						],
-						resourceKey: "projection",
-					}),
+					resource(
+						isObserved
+							? []
+							: null, // eslint-disable-line unicorn/no-null -- Exercise the explicit null returned by the production API/DOM contract.
+						{
+							dependencies: [
+								{
+									...dependency,
+									stateVersion: isObserved ? "covered" : "initial",
+								},
+							],
+							resourceKey: "projection",
+						},
+					),
 				);
 			}),
 			http.get("*/api/v1/tbank-sync/:id", () =>
-				HttpResponse.json((/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+				/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+				HttpResponse.json(
 					{
 						errorCode: null,
 						id: "dependency",
@@ -510,18 +598,22 @@ describe("page-owned screen synchronization", () => {
 						resources: [{ ...dependency, stateVersion: "covered" }],
 						scope: null,
 						state: "succeeded",
-					}
-					/* eslint-enable unicorn/no-null */)),
+					},
+					/* eslint-enable unicorn/no-null */
+				),
 			),
 		);
+
 		const { result } = renderHook(
 			() => {
 				const accounts = useBrokerageAccounts();
 				useScreenSync({ screen: "accounts" }, [accounts]);
+
 				return accounts;
 			},
 			{ wrapper: createQueryWrapper().wrapper },
 		);
+
 		await waitFor(() => expect(result.current.data).toEqual([]));
 		// eslint-disable-next-line unicorn/no-null -- Preserve the API/DOM null sentinel in the expected response.
 		expect(modes).toEqual([null, "observe"]);
@@ -536,9 +628,11 @@ describe("page-owned screen synchronization", () => {
 				HttpResponse.json({ code: "TBANK_UNAVAILABLE" }, { status: 503 }),
 			),
 		);
+
 		const { result } = renderHook(
 			() => {
 				const accounts = useBrokerageAccounts();
+
 				return {
 					accounts,
 					sync: useScreenSync({ screen: "accounts" }, [accounts]),
@@ -546,6 +640,7 @@ describe("page-owned screen synchronization", () => {
 			},
 			{ wrapper: createQueryWrapper().wrapper },
 		);
+
 		await waitFor(() => expect(result.current.accounts.data).toEqual([]));
 		await act(() => result.current.sync.refresh());
 		await waitFor(() => expect(result.current.sync.transportError).toBe(true));