refactor: enforce frontend view model boundaries

src/pages/account/ui/AccountPage/position-groups.test.tsx

@@ -8,8 +8,10 @@ import type { Portfolio } from "@/entities/portfolio";
 import { toAccountPagePositionSections } from "./AccountPage.vm";
 import { PositionSection } from "./components/PositionSection.view";
 
-const position: Portfolio["positions"][number] = (/* 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. */
+
+const position: Portfolio["positions"][number]
+	= {
 		absoluteReturn: { currency: "RUB", value: "25" },
 		account: { id: "a", name: "Основной" },
 		averagePurchasePrice: { currency: "RUB", value: "280" },
@@ -21,18 +23,21 @@ const position: Portfolio["positions"][number] = (/* eslint-disable unicorn/no-n
 		quantity: "1.25",
 		ticker: "SBER",
 		type: "STOCK",
-	}
-/* eslint-enable unicorn/no-null */);
-const second = (/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
-	{
+	};
+
+/* eslint-enable unicorn/no-null */
+/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+const second
+	= {
 		...position,
 		absoluteReturn: null,
 		account: { id: "b", name: "ИИС" },
 		averagePurchasePrice: null,
 		currentValue: null,
 		quantity: "-2",
-	}
-/* eslint-enable unicorn/no-null */);
+	};
+
+/* eslint-enable unicorn/no-null */
 function sections(positions: Portfolio["positions"]) {
 	return toAccountPagePositionSections({
 		cashBalances: [],
@@ -55,9 +60,11 @@ describe("Positions grouped by security", () => {
 			</MantineProvider>,
 		);
 		expect(screen.getAllByText("Сбербанк")).toHaveLength(1);
+
 		const rows = within(
 			screen.getByRole("list", { name: "Позиции по счетам" }),
 		).getAllByRole("listitem");
+
 		expect(rows).toHaveLength(2);
 		expect(
 			within(rows[0]).getByRole("link", { name: "Основной" }),
@@ -77,26 +84,31 @@ describe("Positions grouped by security", () => {
 
 	it("uses ISIN only when FIGI is absent, never merging by name or ticker", () => {
 		expect(
+			/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
 			sections([
-				(/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
-					{ ...position, figi: null }
-				/* eslint-enable unicorn/no-null */),
-				(/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
-					{ ...second, figi: null }
-				/* eslint-enable unicorn/no-null */),
+				{
+					...position,
+					figi: null,
+				},
+				/* eslint-enable unicorn/no-null */ { ...second, figi: null }, // eslint-disable-line unicorn/no-null -- Preserve explicit null in the API fixture.
 			])[0].groups,
 		).toHaveLength(1);
 		expect(
 			sections([position, { ...second, figi: "OTHER-FIGI" }])[0].groups,
 		).toHaveLength(2);
 		expect(
+			/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
 			sections([
-				(/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
-					{ ...position, figi: null, isin: null }
-				/* eslint-enable unicorn/no-null */),
-				(/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
-					{ ...second, figi: null, isin: null }
-				/* eslint-enable unicorn/no-null */),
+				{
+					...position,
+					figi: null,
+					isin: null,
+				},
+				/* eslint-enable unicorn/no-null */ {
+					...second,
+					figi: null, // eslint-disable-line unicorn/no-null -- Preserve explicit null in the API fixture.
+					isin: null, // eslint-disable-line unicorn/no-null -- Preserve explicit null in the API fixture.
+				},
 			])[0].groups,
 		).toHaveLength(2);
 	});
@@ -122,6 +134,7 @@ describe("Positions grouped by security", () => {
 				currentValue: { currency: "USD", value: "1.01" },
 			},
 		];
+
 		const before = structuredClone(source);
 		const [group] = sections(source)[0].groups;
 		expect(