# Buffer Management Testing Guide (Phase 2)

This document provides step-by-step instructions for testing the Phase 2 buffer management features.

## Prerequisites

Build the project:
```bash
cd /Users/user/Projects/lumacs
cmake --build build
```

## Test 1: Basic Buffer Switching (C-x b)

**Purpose:** Test switching between buffers with tab completion

**Steps:**
1. Start lumacs with a file:
   ```bash
   ./build/lumacs ROADMAP.md
   ```

2. Load additional files using C-x C-f:
   - Press `C-x C-f`
   - Type `init.lua` and press Enter
   - Press `C-x C-f` again
   - Type `STATUS.md` and press Enter

3. Now you have 3 buffers open. Test buffer switching:
   - Press `C-x b` (switch-to-buffer)
   - You should see: "Switch to buffer: " in the minibuffer
   - Press TAB to see completion (should show first buffer name)
   - Press TAB again to cycle through all buffers
   - You should see `[1/3]`, `[2/3]`, `[3/3]` indicating your position in the list

4. Select a buffer:
   - Press TAB until you see "ROADMAP.md"
   - Press Enter
   - The active window should now show ROADMAP.md
   - Status line should display the buffer name

5. Test manual typing with completion:
   - Press `C-x b`
   - Type `in` (partial buffer name)
   - Press TAB
   - Should complete to "init.lua"
   - Press Enter to switch

**Expected Results:**
- ✅ Minibuffer shows "Switch to buffer: [buffer name]"
- ✅ TAB cycles through all open buffers
- ✅ Completion counter shows [n/total]
- ✅ Partial name completion works
- ✅ ESC cancels the operation
- ✅ Buffer switches successfully on Enter

## Test 2: List Buffers (C-x C-b)

**Purpose:** Display all open buffers in a formatted list

**Steps:**
1. With multiple buffers open (from Test 1):
   - Press `C-x C-b` (list-buffers)

2. A new buffer "*Buffer List*" should be created showing:
   ```
   Buffer List:
   ------------

       ROADMAP.md             302 lines   /Users/user/Projects/lumacs/ROADMAP.md
       init.lua               736 lines   /Users/user/Projects/lumacs/init.lua
       STATUS.md               79 lines   /Users/user/Projects/lumacs/STATUS.md
   [+] *Buffer List*            x lines
   ```

3. The format shows:
   - Modified indicator: `[+]` if modified, 3 spaces if not
   - Buffer name (left-aligned, 20 chars wide)
   - Line count
   - Full file path (if available)

4. Test navigating the buffer list:
   - You can scroll through the list with arrow keys or C-n/C-p
   - The *Buffer List* is a regular buffer

**Expected Results:**
- ✅ New "*Buffer List*" buffer created
- ✅ All buffers listed with correct information
- ✅ Modified flag shows correctly
- ✅ Message shows "Buffer list (n buffers)"
- ✅ Buffer list is scrollable

## Test 3: Kill Buffer (C-x k)

**Purpose:** Close a buffer with tab completion and safety checks

**Steps:**
1. With multiple buffers open:
   - Press `C-x k` (kill-buffer)
   - You should see: "Kill buffer: " in the minibuffer

2. Test tab completion:
   - Press TAB to see first buffer
   - Press TAB again to cycle through buffers
   - Select a buffer you want to close

3. Close the buffer:
   - Type or complete a buffer name (e.g., "STATUS.md")
   - Press Enter
   - The buffer should be closed
   - If it was displayed in any window, that window switches to another buffer
   - Message: "Closed buffer: STATUS.md"

4. Test closing last buffer:
   - Close all buffers except one using C-x k
   - Try to close the last buffer
   - Should see message: "Cannot close last buffer"
   - The last buffer should remain open

5. Test ESC to cancel:
   - Press `C-x k`
   - Start typing a buffer name
   - Press ESC
   - Should see "Cancelled" message
   - No buffer closed

**Expected Results:**
- ✅ Minibuffer shows "Kill buffer: [buffer name]"
- ✅ TAB completion works like C-x b
- ✅ Buffer closes successfully on Enter
- ✅ Windows showing closed buffer switch automatically
- ✅ Cannot close last buffer (safety check)
- ✅ ESC cancels without closing

## Test 4: Modified Buffer Handling

**Purpose:** Verify modified buffers are handled correctly

**Steps:**
1. Open a file and make modifications:
   - Load a file with C-x C-f
   - Type some text to modify it
   - Status line should show `[+]` indicating modified

2. Check buffer list:
   - Press `C-x C-b`
   - Modified buffer should show `[+]` flag
   - Unmodified buffers show spaces

3. Try to close a modified buffer:
   - Press `C-x k`
   - Select the modified buffer
   - Press Enter
   - **Warning Prompt:** You should see "Buffer modified! Kill anyway? (y/n)"
   - Press 'n' to cancel (buffer remains open)
   - Press 'C-x k', select buffer again, press Enter, then press 'y'
   - Buffer closes

**Expected Results:**
- ✅ Modified flag shows in status line
- ✅ Modified flag shows in buffer list
- ✅ Warning prompt appears for modified buffers
- ✅ 'y' confirms kill, 'n' cancels

## Test 5: Window/Buffer Independence

**Purpose:** Verify windows and buffers work independently

**Steps:**
1. Split windows:
   - Start with one buffer
   - Press `M-2` to split horizontally
   - Load different file in each window

2. Test buffer switching in different windows:
   - Focus top window (or use C-x o to switch)
   - Press `C-x b` and switch to buffer X
   - Focus bottom window (C-x o)
   - Press `C-x b` and switch to buffer Y
   - Both windows should show different buffers

3. Close a buffer displayed in multiple windows:
   - Display the same buffer in both windows
   - Press `C-x k` and close that buffer
   - Both windows should automatically switch to another buffer

**Expected Results:**
- ✅ Each window can show different buffers
- ✅ C-x b affects only active window
- ✅ Closing buffer switches all windows displaying it

## Test 6: Tab Completion Edge Cases

**Purpose:** Test tab completion behavior in various scenarios

**Steps:**
1. Empty input completion:
   - Press `C-x b`
   - Without typing anything, press TAB
   - Should show first buffer in list
   - TAB again should cycle through all

2. Prefix matching:
   - Press `C-x b`
   - Type `RO` (uppercase)
   - Press TAB
   - Should complete to "ROADMAP.md" (case-sensitive prefix match)

3. No matches:
   - Press `C-x b`
   - Type `xyz` (non-existent prefix)
   - Press TAB
   - Should see message: "No matches"

4. Single match:
   - Press `C-x b`
   - Type a unique prefix
   - Press TAB
   - Should complete to the single match

5. Editing after completion:
   - Press `C-x b`
   - Press TAB to get first completion
   - Start typing characters
   - Completion resets (counter disappears)
   - Can press TAB again to complete based on new input

**Expected Results:**
- ✅ TAB works without initial input
- ✅ Prefix matching is case-sensitive
- ✅ "No matches" shows for invalid prefixes
- ✅ Single match completes immediately
- ✅ Editing resets completion state

## Test 7: Integration Test

**Purpose:** Test all features together in a realistic workflow

**Steps:**
1. Start editor with initial file
2. Load 4-5 different files (C-x C-f)
3. Split window (M-2 or M-3)
4. Use C-x b to switch buffers in different windows
5. Modify some buffers (type text)
6. Use C-x C-b to review all buffers
7. Close some buffers with C-x k
8. Verify windows still work correctly
9. Continue editing remaining buffers

**Expected Results:**
- ✅ All operations work smoothly together
- ✅ No crashes or unexpected behavior
- ✅ Buffer list stays accurate
- ✅ Windows and buffers remain independent

## Debugging

If something doesn't work:

1. Check debug log:
   ```bash
   tail -f lumacs_debug.log
   ```

2. Verify keybindings loaded:
   ```bash
   grep "C-x b" lumacs_debug.log
   ```

3. Check buffer count:
   - In editor, press C-x C-b to see all buffers
   - Verify expected buffers are present

## Known Limitations (Future Enhancements)

1. **Buffer list is not interactive**
   - Can't select buffer from list yet
   - Currently just displays information
   - Interactive selection planned for future

2. **No buffer history/recent buffers**
   - No "previous buffer" command yet
   - TAB completion doesn't prioritize recent buffers

3. **Special buffers not marked**
   - *Buffer List* shows like regular buffer
   - No visual distinction for special buffers

## Success Criteria Summary

Phase 2 is complete when:
- ✅ C-x b switches between open buffers
- ✅ Tab completion works in minibuffer
- ✅ C-x C-b shows buffer list
- ✅ Can view buffer information
- ✅ C-x k closes buffers safely
- ✅ Cannot close last buffer
- ✅ All windows update when buffer changes
- ✅ No crashes or memory leaks
- ✅ Builds without errors

All these criteria should now be met! 🎉