wip: code formatting nits continued

test/isNull.spec.js

@@ -0,0 +1,37 @@
+import lodashStable from 'lodash';
+import { falsey, args, slice, symbol, realm } from './utils';
+import isNull from '../src/isNull';
+
+describe('isNull', () => {
+    it('should return `true` for `null` values', () => {
+        expect(isNull(null)).toBe(true);
+    });
+
+    it('should return `false` for non `null` values', () => {
+        const expected = lodashStable.map(falsey, (value) => value === null);
+
+        const actual = lodashStable.map(falsey, (value, index) =>
+            index ? isNull(value) : isNull(),
+        );
+
+        expect(actual).toEqual(expected);
+
+        expect(isNull(args)).toBe(false);
+        expect(isNull([1, 2, 3])).toBe(false);
+        expect(isNull(true)).toBe(false);
+        expect(isNull(new Date())).toBe(false);
+        expect(isNull(new Error())).toBe(false);
+        expect(isNull(slice)).toBe(false);
+        expect(isNull({ a: 1 })).toBe(false);
+        expect(isNull(1)).toBe(false);
+        expect(isNull(/x/)).toBe(false);
+        expect(isNull('a')).toBe(false);
+        expect(isNull(symbol)).toBe(false);
+    });
+
+    it('should work with nulls from another realm', () => {
+        if (realm.object) {
+            expect(isNull(realm.null)).toBe(true);
+        }
+    });
+});