test: add failing tests for msecs in v7

test/unit/v7.test.js

@@ -24,6 +24,7 @@ import v7 from '../../src/v7.js';
 
 describe('v7', () => {
   const msecsFixture = 1645557742000;
+  const msecsFutureFixture = Date.UTC('2100');
   const seqFixture = 0x661b189b;
 
   const randomBytesFixture = [
@@ -63,6 +64,26 @@ describe('v7', () => {
     assert.strictEqual(id.indexOf('017f22e2'), 0);
   });
 
+  test('explicit options.msecs after a standard call randomises seq', () => {
+    const id1 = v7();
+    const id2 = v7({
+      msecs: msecsFixture,
+    });
+
+    assert.notDeepStrictEqual(id1.slice(14, 23), id2.slice(14, 23));
+  });
+
+  test('providing current options.msecs after past options.msecs works', () => {
+    const id1 = v7({
+      msecs: msecsFixture,
+    });
+    const id2 = v7({
+      msecs: Date.now(),
+    });
+
+    assert.notDeepStrictEqual(id1.slice(0, 13), id2.slice(0, 13));
+  });
+
   test('fills one UUID into a buffer as expected', () => {
     const buffer = [];
     const result = v7(
@@ -169,4 +190,11 @@ describe('v7', () => {
 
     assert(uuid.indexOf('fff') !== 15);
   });
+
+  test('explicit options.msecs in the future produces expected result', () => {
+    const id = v7({
+      msecs: msecsFutureFixture,
+    });
+    assert.match(id, /^3bb2cc3/);
+  });
 });