Replace redux with TanStack Query and an auth context

src/queries/queryClient.test.ts

@@ -0,0 +1,43 @@
+import type { Query } from '@tanstack/react-query';
+
+import { ApiError } from '@/errors';
+import { appQueryClient, persistOptions } from '@/queries/queryClient';
+
+const queryDefaults = appQueryClient.getDefaultOptions().queries!;
+
+describe('retry', () => {
+  const retry = queryDefaults.retry as (failureCount: number, error: Error) => boolean;
+
+  it('retries a failed request once', () => {
+    expect(retry(0, new Error('network down'))).toBe(true);
+    expect(retry(1, new Error('network down'))).toBe(false);
+  });
+
+  it('never retries a 401, whose token is dead', () => {
+    expect(retry(0, new ApiError({ detail: 'Ugyldig token.' }, 401))).toBe(false);
+  });
+
+  it('retries other API errors', () => {
+    expect(retry(0, new ApiError({ detail: 'Serverfeil' }, 500))).toBe(true);
+  });
+
+  it('does not retry mutations', () => {
+    expect(appQueryClient.getDefaultOptions().mutations?.retry).toBe(0);
+  });
+});
+
+describe('persistOptions', () => {
+  it('only dehydrates successful queries', () => {
+    const shouldDehydrateQuery = persistOptions.dehydrateOptions!.shouldDehydrateQuery!;
+
+    expect(shouldDehydrateQuery({ state: { status: 'success' } } as unknown as Query)).toBe(true);
+    expect(shouldDehydrateQuery({ state: { status: 'error' } } as unknown as Query)).toBe(false);
+    expect(shouldDehydrateQuery({ state: { status: 'pending' } } as unknown as Query)).toBe(false);
+  });
+
+  it('keeps the persisted cache for 90 days of offline proof, within gcTime', () => {
+    expect(persistOptions.maxAge).toBe(90 * 24 * 60 * 60 * 1000);
+    // must stay ≥ maxAge; finite values this large overflow setTimeout and GC immediately
+    expect(queryDefaults.gcTime).toBe(Infinity);
+  });
+});