test: add unit tests for search reducer (#67698)

client/src/components/search/redux/index.test.js

@@ -0,0 +1,42 @@
+import { describe, it, expect } from 'vitest';
+
+import {
+  reducer,
+  toggleSearchDropdown,
+  toggleSearchFocused,
+  updateSearchQuery
+} from './index';
+
+describe('search reducer', () => {
+  it('toggles search dropdown when payload is undefined', () => {
+    const state = reducer(undefined, toggleSearchDropdown());
+    expect(state.isSearchDropdownEnabled).toBe(false);
+  });
+
+  it('sets dropdown when boolean payload is provided', () => {
+    const state = reducer(undefined, toggleSearchDropdown(false));
+    expect(state.isSearchDropdownEnabled).toBe(false);
+  });
+
+  it('updates search query', () => {
+    const state = reducer(undefined, updateSearchQuery('react'));
+    expect(state.query).toBe('react');
+  });
+
+  it('updates focus state', () => {
+    const state = reducer(undefined, toggleSearchFocused(true));
+    expect(state.isSearchBarFocused).toBe(true);
+  });
+
+  it('supports non-boolean focus payload', () => {
+    const state = reducer(undefined, toggleSearchFocused('banana'));
+    expect(state.isSearchBarFocused).toBe('banana');
+  });
+
+  it('returns same state when focus value does not change', () => {
+    const first = reducer(undefined, toggleSearchFocused(false));
+    const second = reducer(first, toggleSearchFocused(false));
+
+    expect(second).toBe(first);
+  });
+});