Regression tests for immutable-js#1325

leebyron · leebyron · commit eeae1bdec33e · 2017-10-02T12:59:49.000-07:00
diff --git a/__tests__/hash.ts b/__tests__/hash.ts
@@ -0,0 +1,41 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+///<reference path='../resources/jest.d.ts'/>
+
+import * as jasmineCheck from 'jasmine-check';
+jasmineCheck.install();
+
+import { hash } from '../';
+
+describe('hash', () => {
+
+  it('stable hash of well known values', () => {
+    expect(hash(true)).toBe(1);
+    expect(hash(false)).toBe(0);
+    expect(hash(0)).toBe(0);
+    expect(hash(null)).toBe(0);
+    expect(hash(undefined)).toBe(0);
+    expect(hash('a')).toBe(97);
+    expect(hash('immutable-js')).toBe(510203252);
+    expect(hash(123)).toBe(123);
+  });
+
+  it('generates different hashes for decimal values', () => {
+    expect(hash(123.456)).toBe(884763256);
+    expect(hash(123.4567)).toBe(887769707);
+  });
+
+  const genValue = gen.oneOf([gen.string, gen.int]);
+
+  check.it('generates unsigned 31-bit integers', [genValue], value => {
+    const hashVal = hash(value);
+    expect(hashVal % 1).toBe(0);
+    expect(hashVal).toBeLessThan(Math.pow(2, 31));
+  });
+
+});
