Allow clearing and replacing auction bids

tests/integer-input.test.ts

@@ -0,0 +1,19 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { integerInputValue } from '../lib/integer-input';
+
+void test('clearing a numeric draft stays invalid until a replacement is entered', () => {
+  for (const replacement of ['2', '5', '9', '20']) {
+    assert.equal(integerInputValue('1'), 1);
+    assert.ok(Number.isNaN(integerInputValue('')));
+    assert.equal(integerInputValue(replacement), Number(replacement));
+  }
+});
+
+void test('explicit zero remains distinct from an empty or non-integer bid', () => {
+  assert.equal(integerInputValue('0'), 0);
+  assert.equal(integerInputValue('02'), 2);
+  for (const draft of ['', ' ', '-', '1.5', 'Infinity', '9007199254740992']) {
+    assert.ok(Number.isNaN(integerInputValue(draft)), draft);
+  }
+});