Update TODO.md and remove obsolete unit test comments

- Remove 5 obsolete "TODO: Unit test this" comments from eventloop.go
  for event types that already have comprehensive test coverage
- Keep TODO comment for FcntlEvent which still needs tests
- Reorganize TODO.md with prioritized task list based on all TODOs
  found across the codebase
- Add priority levels: High (core functionality), Medium (additional
  syscalls), Low (less common features), and General improvements
- Document completed tasks to acknowledge test coverage achievements

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

2 files changed, 73 insertions, 55 deletions

diff --git a/TODO.md b/TODO.md
index d56496d..eb0c5b1 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,50 +1,73 @@
-# TODO - Eventloop Test Coverage
-
-## Remaining Helper Functions
-- [x] Create helper functions for NameEvent (makeEnterNameEvent/makeExitNameEvent)
-- [x] Create helper functions for NullEvent (makeEnterNullEvent/makeExitNullEvent)  
-- [x] Create helper functions for Dup3Event (makeEnterDup3Event/makeExitDup3Event)
-
-## Remaining Test Cases
-
-### FdEvent Syscalls
-- [x] Add test case for fsync syscall
-- [x] Add test case for ftruncate syscall
-
-### PathEvent Syscalls  
-- [x] Add test case for unlink syscall
-- [x] Add test case for creat syscall
-- [x] Add test case for stat syscall
-- [x] Add test case for access syscall
-
-### NameEvent Syscalls
-- [x] Add test case for rename syscall
-- [x] Add test case for link syscall
-- [x] Add test case for symlink syscall
-
-### NullEvent Syscalls
-- [x] Add test case for sync syscall
-- [x] Add test case for io_uring_setup syscall
-
-### Dup3Event Syscalls
-- [x] Add test case for dup3 syscall
-
-## Advanced Test Cases
-
-### File Descriptor Lifecycle
-- [x] Test that fd from openat is properly tracked in subsequent read/write/close operations
-- [x] Test dup/dup2/dup3 creating new file descriptors
-- [x] Test close removing fd from tracking
-- [x] Test multiple file descriptors being tracked simultaneously
-
-### Edge Cases
-- [x] Test missing enter events (only exit event received)
-- [x] Test missing exit events (only enter event received)
-- [x] Test mismatched enter/exit pairs
-- [x] Test out-of-order events
-- [x] Test events from different threads/processes
-
-### Filtering and Comm Tracking
-- [x] Test that comm names are properly propagated across syscalls
-- [x] Test filter behavior for each event type
-- [x] Test comm filter enable/disable functionality
\ No newline at end of file
+# TODO - I/O Riot NG Development Tasks
+
+## High Priority (Core functionality)
+
+### 1. Add unit test for FcntlEvent handling
+- Test F_SETFL flag modification
+- Test F_DUPFD file descriptor duplication  
+- Test F_DUPFD_CLOEXEC with O_CLOEXEC flag
+- Location: internal/eventloop.go:305
+
+### 2. Implement byte count tracking for read/write syscalls
+- Track number of bytes read/written in each I/O operation
+- Add to flamegraph statistics
+- Location: internal/flamegraph/counter.go:11
+
+## Medium Priority (Additional syscalls)
+
+### 3. Implement copy_file_range syscall
+- Capture source and destination file descriptors
+- Track byte count copied
+- Location: internal/eventloop.go:353
+
+### 4. Implement mmap/msync syscalls
+- Track memory-mapped file operations
+- Capture file descriptor and memory addresses
+- Location: internal/eventloop.go:356
+
+### 5. Implement sync_file_range syscall
+- Capture file descriptor and range parameters
+- Track selective file synchronization
+- Location: internal/eventloop.go:358
+
+## Low Priority (Less common syscalls)
+
+### 6. Implement open_by_handle_at syscall
+- Handle file access by handle
+- Location: internal/eventloop.go:354
+
+### 7. Implement name_to_handle_at syscall  
+- Convert pathname to handle
+- Location: internal/eventloop.go:355
+
+### 8. Implement getcwd syscall
+- Track current working directory queries
+- Location: internal/eventloop.go:357
+
+### 9. Add sys_enter_open_by_handle_at to BPF
+- Update BPF tracepoint generation
+- Location: internal/c/generate_tracepoints_c.raku:5
+
+### 10. Enhance io_uring_enter capture with FD tracking
+- Currently captured but without file descriptor context
+- Location: internal/eventloop.go:359
+
+## General Improvements
+
+### 11. Write comprehensive unit tests
+- Increase overall test coverage
+- Location: internal/ior.go:21
+
+### 12. Write integration tests
+- Use C/Cgo to simulate real I/O operations
+- Test end-to-end functionality
+- Location: internal/ior.go:22
+
+## Completed Tasks ✓
+
+All previously listed test cases have been implemented:
+- Helper functions for all event types
+- Test cases for all basic syscalls
+- File descriptor lifecycle tests
+- Edge case handling tests
+- Filtering and comm tracking tests
\ No newline at end of file
diff --git a/internal/eventloop.go b/internal/eventloop.go
index 679d69f..9a64647 100644
--- a/internal/eventloop.go
+++ b/internal/eventloop.go
@@ -219,13 +219,11 @@ func (e *eventLoop) tracepointExited(exitEv event.Event, ch chan<- *event.Pair)
 		}
 		e.comms[openEv.Tid] = comm
 
-	// TODO: Unit test this
 	case *NameEvent:
 		nameEvent := ep.EnterEv.(*NameEvent)
 		ep.File = file.NewOldnameNewname(nameEvent.Oldname[:], nameEvent.Newname[:])
 		ep.Comm = e.comm(ep.EnterEv.GetTid())
 
-	// TODO: Unit test this
 	case *PathEvent:
 		nameEvent := ep.EnterEv.(*PathEvent)
 		if ep.Is(SYS_ENTER_CREAT) {
@@ -240,7 +238,6 @@ func (e *eventLoop) tracepointExited(exitEv event.Event, ch chan<- *event.Pair)
 		}
 		ep.Comm = e.comm(ep.EnterEv.GetTid())
 
-	// TODO: Unit test this
 	case *FdEvent:
 		fd := ep.EnterEv.(*FdEvent).Fd
 		if file_, ok := e.files[fd]; ok {
@@ -268,7 +265,6 @@ func (e *eventLoop) tracepointExited(exitEv event.Event, ch chan<- *event.Pair)
 			}
 		}
 
-	// TODO: Unit test this
 	case *Dup3Event:
 		dup3Event := ep.EnterEv.(*Dup3Event)
 		fd := int32(dup3Event.Fd)
@@ -294,7 +290,6 @@ func (e *eventLoop) tracepointExited(exitEv event.Event, ch chan<- *event.Pair)
 			e.files[newFd] = duppedFdFile
 		}
 
-	// TODO: Unit test this
 	case *NullEvent:
 		ep.Comm = e.comm(ep.EnterEv.GetTid())
 		if !e.filter.eventPair(ep) {