test: add check for many messages and a partial

Author: nbbeeken

test/unit/cmap/connection.test.ts

@@ -323,7 +323,7 @@ describe('new Connection()', function () {
  });
  });
 
- describe('SizedMessageTransform', function () {
+ describe.only('SizedMessageTransform', function () {
  it('parses chunks of wire messages', function () {
  const stream = new SizedMessageTransform({ connection: {} as any });
  // Message of length 4 + 4 = 8
@@ -337,7 +337,7 @@ describe('new Connection()', function () {
  expect(stream.read(1)).to.equal(null);
  });
 
- it('parses many wire messages when chunk arrives', function () {
+ it('parses many wire messages when a single chunk arrives', function () {
  const stream = new SizedMessageTransform({ connection: {} as any });
 
  let dataCount = 0;
@@ -357,7 +357,32 @@ describe('new Connection()', function () {
  expect(dataCount).to.equal(3);
  });
 
- it('waits for a drain event when destination needs backpressure', async function () {
+ it('parses many wire messages when a single chunk arrives and processes the remaining partial when it is complete', function () {
+ const stream = new SizedMessageTransform({ connection: {} as any });
+
+ let dataCount = 0;
+ stream.on('data', () => {
+ dataCount += 1;
+ });
+
+ // 3 messages of size 8
+ stream.write(
+ Buffer.from([
+ ...[8, 0, 0, 0, 0, 0, 0, 0],
+ ...[8, 0, 0, 0, 0, 0, 0, 0],
+ ...[8, 0, 0, 0, 0, 0, 0, 0],
+ ...[8, 0, 0, 0, 0, 0] // two shy of 8
+ ])
+ );
+
+ expect(dataCount).to.equal(3);
+
+ stream.write(Buffer.from([0, 0])); // the rest of the last 8
+
+ expect(dataCount).to.equal(4);
+ });
+
+ it('throws an error when backpressure detected', async function () {
  const stream = new SizedMessageTransform({ connection: {} as any });
  const destination = new Writable({
  highWaterMark: 1,