chore: updated FEATURES.md

FEATURES.md

@@ -213,11 +213,11 @@
 - [x] `:set number!` - Toggle line numbers
 - [x] `:set tabstop=N` - Set tab width
 - [x] `:register {name}` - Show register contents
-- [ ] `:w` - Write file
-- [ ] `:q` - Quit
-- [ ] `:wq` - Write and quit
-- [ ] `:q!` - Force quit
-- [ ] `:e {file}` - Edit file
+- [x] `:w` - Write file
+- [x] `:q` - Quit
+- [x] `:wq` - Write and quit
+- [x] `:q!` - Force quit
+- [x] `:e {file}` - Edit file
 - [ ] `:bn` / `:bp` - Next/previous buffer
 - [ ] `:{range}` - Go to line
 - [ ] `:%s/old/new/g` - Search and replace
@@ -266,13 +266,13 @@ Buffers are in-memory representations of files. A buffer exists for each open fi
 ### Buffer Model
 - [x] Buffer struct (id, filename, lines, modified flag, cursor position)
 - [ ] Buffer list/manager
-- [ ] Current buffer tracking
+- [x] Current buffer tracking
 - [ ] Buffer-local settings (tabstop, filetype, etc.)
-- [ ] Modified/dirty state tracking
-- [ ] Read-only buffer support
+- [x] Modified/dirty state tracking
+- [x] Read-only buffer support
 
 ### Buffer Navigation
-- [ ] `:e {file}` - Edit file (open in new buffer or switch to existing)
+- [x] `:e {file}` - Edit file (open in new buffer or switch to existing)
 - [ ] `:bn` / `:bnext` - Next buffer
 - [ ] `:bp` / `:bprev` - Previous buffer
 - [ ] `:b {name}` - Switch to buffer by name (partial match)
@@ -286,9 +286,9 @@ Buffers are in-memory representations of files. A buffer exists for each open fi
 - [ ] `:bd` / `:bdelete` - Delete buffer (close file)
 - [ ] `:bd!` - Force delete buffer (discard changes)
 - [ ] `:bw` / `:bwipeout` - Wipe buffer (remove completely)
-- [ ] `:w` - Write current buffer to file
-- [ ] `:w {file}` - Write buffer to specific file
-- [ ] `:wa` - Write all modified buffers
+- [x] `:w` - Write current buffer to file
+- [x] `:w {file}` - Write buffer to specific file
+- [x] `:wa` - Write all modified buffers
 - [ ] `:sav {file}` - Save as (write to new file, switch to it)
 
 ### Buffer State
@@ -309,8 +309,8 @@ Buffers are in-memory representations of files. A buffer exists for each open fi
 
 ### Hidden Buffers
 - [ ] `:set hidden` - Allow switching with unsaved changes
-- [ ] Prompt to save when closing modified buffer
-- [ ] `:q` behavior with modified buffers
+- [x] Prompt to save when closing modified buffer
+- [x] `:q` behavior with modified buffers
 
 ### Argument List (Advanced)
 - [ ] `:args` - Show argument list
@@ -381,8 +381,8 @@ Buffers are in-memory representations of files. A buffer exists for each open fi
 - [ ] Color column (ruler)
 
 ### Files
-- [ ] File reading
-- [ ] File writing
+- [x] File reading
+- [x] File writing
 - [ ] Auto-save
 - [ ] Backup files
 - [ ] Swap files
@@ -405,9 +405,49 @@ Buffers are in-memory representations of files. A buffer exists for each open fi
 
 ---
 
-## Testing Coverage
+### Well Tested - Editor Core
 
-### Well Tested
+#### Command Execution (179 tests)
+- [x] Command parsing and validation
+- [x] Command lookup and prefix matching
+- [x] Force flag handling (!)
+- [x] Write commands (`:w`, `:w {file}`, `:w!`)
+- [x] Write all commands (`:wa`, `:wall`, `:wa!`)
+- [x] Quit commands (`:q`, `:q!`, `:qa`, `:qa!`)
+- [x] Write-quit commands (`:wq`, `:wq!`, `:wqa`, `:wqa!`)
+- [x] Edit command (`:e {file}`)
+- [x] Register display (`:register`, `:reg {name}`)
+- [x] Set commands (`:set number`, `:set tabstop=N`, etc.)
+- [x] Setting lookup and validation
+- [x] Buffer-level readonly protection
+- [x] Scratch buffer write protection
+- [x] Force write bypassing readonly/scratch checks
+- [x] Multiple buffer write operations
+- [x] File write error handling (permissions, paths)
+- [x] Modified buffer tracking
+- [x] Unicode filename and content handling
+- [x] Edge cases (empty args, long filenames, special chars)
+
+#### Program Initialization (70 tests)
+- [x] Empty program creation
+- [x] File program with nonexistent files (new file buffers)
+- [x] File program with existing files (content loading)
+- [x] Line ending handling (Unix `\n`, Windows `\r\n`, mixed)
+- [x] Tab to space conversion based on TabStop
+- [x] Unicode content preservation (CJK, emoji)
+- [x] File extension and type detection
+- [x] Buffer state initialization (flags, metadata)
+- [x] Large file handling (10,000+ lines)
+- [x] Long line handling (10,000+ chars)
+- [x] Empty file handling
+- [x] Builder pattern method chaining
+- [x] Program option accumulation
+- [x] Model state defaults (settings, registers, mode)
+- [x] Error handling (permissions, invalid paths)
+- [x] Integration workflows (end-to-end)
+- [x] Edge cases (empty filenames, relative paths, dot files)
+
+### Moderately Tested
 - [x] Basic motions (h, j, k, l)
 - [x] Word motions (w, e, b)
 - [x] Jump motions (G, gg, 0, $, _, ^, |)
@@ -422,6 +462,5 @@ Buffers are in-memory representations of files. A buffer exists for each open fi
 - [x] Visual modes (v, V, ctrl+v)
 - [x] Visual mode with motions
 - [x] Delete actions (x, D)
-- [x] Command mode basics
 - [x] Register behavior