test: add tests for toFormatters

src/tests/helpers/to-formatters.test.ts

@@ -0,0 +1,29 @@
+import { expect } from '@open-wc/testing';
+
+import { toFormatters } from '../../helpers/to-formatters';
+import type { Formatters } from '../../typings';
+
+describe(toFormatters.name, () => {
+  it('returns formatters', () => {
+    const testLocale = 'en-US';
+    const result = toFormatters(testLocale);
+
+    expect(result).haveOwnProperty('locale', testLocale);
+
+    const props: (keyof Omit<Formatters, 'locale'>)[] = [
+      'dateFormat',
+      'dayFormat',
+      'fullDateFormat',
+      'longMonthFormat',
+      'longMonthYearFormat',
+      'longWeekdayFormat',
+      'narrowWeekdayFormat',
+      'yearFormat',
+    ];
+
+    props.forEach(
+      n =>
+        expect(result).haveOwnProperty(n)
+    );
+  });
+});