diff --git a/OSBindings/Mac/Clock SignalTests/PCMPatchedTrackTests.mm b/OSBindings/Mac/Clock SignalTests/PCMPatchedTrackTests.mm
index df5514aa6..467c65d7d 100644
--- a/OSBindings/Mac/Clock SignalTests/PCMPatchedTrackTests.mm	
+++ b/OSBindings/Mac/Clock SignalTests/PCMPatchedTrackTests.mm	
@@ -56,17 +56,15 @@
 - (void)testSingleSplice
 {
 	std::shared_ptr<Storage::Disk::Track> patchableTrack = self.patchableTogglingTrack;
-	Storage::Disk::PCMPatchedTrack *patchable = dynamic_cast<Storage::Disk::PCMPatchedTrack *>(patchableTrack.get());
-	if(patchable)
-	{
-		// add a single one, at 1/32 length at 3/128. So that should shift the location of the second flux transition
-		Storage::Disk::PCMSegment one_segment;
-		one_segment.data = {0xff};
-		one_segment.number_of_bits = 1;
-		one_segment.length_of_a_bit.length = 1;
-		one_segment.length_of_a_bit.clock_rate = 32;
-		patchable->add_segment(Storage::Time(3, 128), one_segment);
-	}
+	Storage::Disk::PCMPatchedTrack *patchable = static_cast<Storage::Disk::PCMPatchedTrack *>(patchableTrack.get());
+
+	// add a single one, at 1/32 length at 3/128. So that should shift the location of the second flux transition
+	Storage::Disk::PCMSegment one_segment;
+	one_segment.data = {0xff};
+	one_segment.number_of_bits = 1;
+	one_segment.length_of_a_bit.length = 1;
+	one_segment.length_of_a_bit.clock_rate = 32;
+	patchable->add_segment(Storage::Time(3, 128), one_segment);
 
 	Storage::Time total_length;
 	std::vector<Storage::Disk::Track::Event> events;
@@ -84,4 +82,85 @@
 	XCTAssert(total_length == Storage::Time(1), @"Total track length should still be 1");
 }
 
+- (void)testLeftReplace
+{
+	std::shared_ptr<Storage::Disk::Track> patchableTrack = self.patchableTogglingTrack;
+	Storage::Disk::PCMPatchedTrack *patchable = static_cast<Storage::Disk::PCMPatchedTrack *>(patchableTrack.get());
+
+	Storage::Disk::PCMSegment zero_segment;
+	zero_segment.data = {0x00};
+	zero_segment.number_of_bits = 8;
+	zero_segment.length_of_a_bit.length = 1;
+	zero_segment.length_of_a_bit.clock_rate = 16;
+	patchable->add_segment(Storage::Time(0), zero_segment);
+
+	Storage::Time total_length;
+	std::vector<Storage::Disk::Track::Event> events;
+	while(1)
+	{
+		events.push_back(patchableTrack->get_next_event());
+		total_length += events.back().length;
+		if(events.back().type == Storage::Disk::Track::Event::IndexHole) break;
+	}
+
+	XCTAssert(events.size() == 17, @"Should still be 17 total events");
+	XCTAssert(events[0].length == Storage::Time(33, 64), @"First event should not occur until 33/64");
+	XCTAssert(total_length == Storage::Time(1), @"Total track length should still be 1");
+}
+
+- (void)testRightReplace
+{
+	std::shared_ptr<Storage::Disk::Track> patchableTrack = self.patchableTogglingTrack;
+	Storage::Disk::PCMPatchedTrack *patchable = static_cast<Storage::Disk::PCMPatchedTrack *>(patchableTrack.get());
+
+	Storage::Disk::PCMSegment zero_segment;
+	zero_segment.data = {0x00};
+	zero_segment.number_of_bits = 8;
+	zero_segment.length_of_a_bit.length = 1;
+	zero_segment.length_of_a_bit.clock_rate = 16;
+	patchable->add_segment(Storage::Time(1, 2), zero_segment);
+
+	Storage::Time total_length;
+	std::vector<Storage::Disk::Track::Event> events;
+	while(1)
+	{
+		events.push_back(patchableTrack->get_next_event());
+		total_length += events.back().length;
+		if(events.back().type == Storage::Disk::Track::Event::IndexHole) break;
+	}
+
+	XCTAssert(events.size() == 17, @"Should still be 17 total events");
+	XCTAssert(events[16].length == Storage::Time(33, 64), @"Final event should take 33/64");
+	XCTAssert(total_length == Storage::Time(1), @"Total track length should still be 1");
+}
+
+- (void)testMultiReplace
+{
+	std::shared_ptr<Storage::Disk::Track> patchableTrack = self.patchableTogglingTrack;
+	Storage::Disk::PCMPatchedTrack *patchable = static_cast<Storage::Disk::PCMPatchedTrack *>(patchableTrack.get());
+
+	for(int c = 0; c < 4; c++)
+	{
+		Storage::Disk::PCMSegment segment;
+		segment.data = {0xff};
+		segment.number_of_bits = 8;
+		segment.length_of_a_bit.length = 1;
+		segment.length_of_a_bit.clock_rate = 32;
+		patchable->add_segment(Storage::Time(c, 4), segment);
+	}
+
+	Storage::Time total_length;
+	std::vector<Storage::Disk::Track::Event> events;
+	while(1)
+	{
+		events.push_back(patchableTrack->get_next_event());
+		total_length += events.back().length;
+		if(events.back().type == Storage::Disk::Track::Event::IndexHole) break;
+	}
+
+	XCTAssert(events.size() == 17, @"Should still be 17 total events");
+	XCTAssert(events[16].length == Storage::Time(33, 64), @"Final event should take 33/64");
+	XCTAssert(total_length == Storage::Time(1), @"Total track length should still be 1");
+}
+
 @end