Test original behavior too

Author: emurray2

Tests/AudioKitEXTests/SequencerTrackTests.swift

@@ -131,6 +131,13 @@ class SequencerTrackTests: XCTestCase {
 
         XCTAssertEqual(track.length, 4, "Track length shouldn't be extended with chord duration less than existing track length")
 
+        track.add(noteNumber: 60, position: 0.0, duration: 1.0)
+        track.add(noteNumber: 60, position: 1.0, duration: 1.0)
+        track.add(noteNumber: 60, position: 2.0, duration: 1.0)
+        track.add(noteNumber: 60, position: 3.0, duration: 1.0)
+
+        XCTAssertEqual(track.length, 4.01, "Track length should be extended with note event position + duration greater or equal to existing track length")
+
         track.playFromStart()
         XCTAssertTrue(track.isPlaying)
         let audio = engine.startTest(totalDuration: 5.0)