add test for demoting indexer

test/basic.js

@@ -1460,6 +1460,68 @@ test('basic - promote writer to indexer', async t => {
   t.ok(b.isActiveIndexer)
 })
 
+test('basic - demote indexer to writer', async t => {
+  t.plan(13)
+
+  const { bases } = await create(2, t, { apply })
+
+  const [a, b] = bases
+
+  // add writer
+  await addWriterAndSync(a, b)
+
+  t.is(a.linearizer.indexers.length, 2)
+  t.is(b.linearizer.indexers.length, 2)
+
+  t.ok(b.isIndexer)
+  t.ok(b.isActiveIndexer)
+
+  await b.append('message')
+  await confirm([a, b])
+
+  t.is(a.view.indexedLength, 1)
+  t.is(b.view.indexedLength, 1)
+
+  // promote writer
+  await a.append({ remove: b4a.toString(b.local.key, 'hex') })
+
+  const event = new Promise(resolve => b.on('is-non-indexer', resolve))
+
+  await confirm([a, b])
+
+  t.is(a.linearizer.indexers.length, 1)
+  t.is(b.linearizer.indexers.length, 1)
+
+  await replicateAndSync([a, b])
+
+  await t.execution(event)
+
+  t.is(b.linearizer.indexers.length, 1)
+  t.absent(b.isIndexer)
+  t.absent(b.isActiveIndexer)
+
+  // flush active writer set
+  await a.append(null)
+
+  t.is(a.activeWriters.size, 1)
+
+  async function apply (batch, view, base) {
+    for (const { value } of batch) {
+      if (value.add) {
+        await base.addWriter(b4a.from(value.add, 'hex'))
+        continue
+      }
+
+      if (value.remove) {
+        await base.removeWriter(b4a.from(value.remove, 'hex'))
+        continue
+      }
+
+      await view.append(value)
+    }
+  }
+})
+
 test('basic - add new indexer after removing', async t => {
   const { bases } = await create(3, t, { apply: applyWithRemove })
   const [a, b, c] = bases