test: add api surface test v4()

test/unit/unit.test.js

@@ -7,6 +7,7 @@ import sha1 from '../../src/sha1.js';
 import sha1Browser from '../../src/sha1-browser.js';
 import v1 from '../../src/v1.js';
 import v3 from '../../src/v3.js';
+import v4 from '../../src/v4.js';
 import v5 from '../../src/v5.js';
 
 describe('rng', () => {
@@ -136,6 +137,78 @@ describe('v1', () => {
   });
 });
 
+describe('v4', () => {
+  const randomBytesFixture = [
+    0x10,
+    0x91,
+    0x56,
+    0xbe,
+    0xc4,
+    0xfb,
+    0xc1,
+    0xea,
+    0x71,
+    0xb4,
+    0xef,
+    0xe1,
+    0x67,
+    0x1c,
+    0x58,
+    0x36,
+  ];
+  const expectedBytes = [16, 145, 86, 190, 196, 251, 65, 234, 177, 180, 239, 225, 103, 28, 88, 54];
+
+  test('subsequent UUIDs are different', () => {
+    const id1 = v4();
+    const id2 = v4();
+    assert(id1 !== id2);
+  });
+
+  test('explicit options.random produces expected result', () => {
+    const id = v4({
+      random: randomBytesFixture,
+    });
+    assert.strictEqual(id, '109156be-c4fb-41ea-b1b4-efe1671c5836');
+  });
+
+  test('explicit options.rng produces expected result', () => {
+    const id = v4({
+      rng: () => randomBytesFixture,
+    });
+    assert.strictEqual(id, '109156be-c4fb-41ea-b1b4-efe1671c5836');
+  });
+
+  test('fills one UUID into a buffer as expected', () => {
+    const buffer = new Array();
+    v4(
+      {
+        random: randomBytesFixture,
+      },
+      buffer,
+    );
+    assert.deepEqual(buffer, expectedBytes);
+  });
+
+  test('fills two UUIDs into a buffer as expected', () => {
+    const buffer = new Array();
+    v4(
+      {
+        random: randomBytesFixture,
+      },
+      buffer,
+      0,
+    );
+    v4(
+      {
+        random: randomBytesFixture,
+      },
+      buffer,
+      16,
+    );
+    assert.deepEqual(buffer, expectedBytes.concat(expectedBytes));
+  });
+});
+
 describe('v5', () => {
   const HASH_SAMPLES = [
     {