End-to-End (E2E) & Functional Testing

To ensure that releases do not introduce regressions (especially regarding terminal rendering, PTY initialization, and UI interactivity across different terminals), mantis uses a combination of automated and manual E2E/functional testing.

1. Test Dataset (`e2e/data/`)

A dedicated test dataset is located in the e2e/data/ directory. It contains static sample files representing different edge cases and supported file types:

rust_sample.rs: Rust code structure to verify syntax highlighting, search, and line numbers.
json_sample.json: Minified JSON to verify automatic pretty-printing.
yaml_sample.yml: Nested YAML with anchors (&) and aliases (*) to verify indentation-based folding and counts.
python_sample.py: Python source file.
markdown_sample.md: Markdown document.
long_lines.txt: Extremely long lines of text to verify word-wrapping behavior.
crlf_sample.txt: Text file with Windows (\r\n) line endings to verify normalization to LF.
bom_utf8_sample.txt: UTF-8 file with a Byte Order Mark (BOM) to verify BOM detection.
binary_sample.bin: Binary data containing NUL bytes to verify binary placeholder rendering.

2. Automated E2E Testing

Automated E2E tests are split into two parts:

A. Cargo Integration Tests (`tests/e2e_tests.rs`)

Runs programmatically using a simulated App state and a TestBackend to verify file parsing, encoding detection, search matching, and folding logic.

B. Whole-Binary TUI Smoke Test (`scripts/ci-e2e.py`)

Spawns the compiled mantis binary under a pseudo-terminal (PTY) in Python, sets the terminal size, waits for it to render the TUI screen, verifies file tree listings, and exits cleanly with a simulated q keystroke. This verifies real-world raw-mode terminal initialization.

Running Automated E2E Tests

To run all automated E2E tests locally:

just test-e2e

These tests are also run automatically in CI on every Pull Request (in ci.yml) and push to main (in main.yml).

3. Manual Testing Checklist

Run through these verification steps on your target terminals before a release:

Windows Terminal (PowerShell & WSL)
iTerm2
Ghostty
Alacritty

Launch Command

Launch mantis targeting the test dataset directory:

cargo run -- ./e2e/data

Checklist Steps

Category	Steps to Execute	Expected Behavior
1. File Tree & Nav	Navigate tree with Up/Down arrows or mouse scroll wheel. Double-click or press Enter on directories.	Smooth movement without cursor drift or overlaps.
2. Binary Files	Select `binary_sample.bin`.	Displays the binary placeholder: `[binary file — BIN file, 125 B]` and shows instructions.
3. JSON Pretty Print	Select `json_sample.json`.	The minified JSON is pretty-printed across multiple lines, highlighted, and supports folding.
4. YAML Folding	Select `yaml_sample.yml`. Focus content pane (Tab). Move cursor to a parent line (e.g. `production:`) and press `Space`.	The block collapses. Gutter shows folding indicators (`+` / `-`). Scrolling is adjusted correctly.
5. Word Wrap	Select `long_lines.txt`. Toggle word wrap via the command palette (`Ctrl+P` and type `wrap`) or by pressing its keybinding (if configured).	Long lines wrap cleanly at terminal edge, line numbers align to physical lines, no horizontal scroll needed.
6. Search	Select `rust_sample.rs`. Press `/` to open search. Type `Rectangle`. Press Enter. Press `n`/`N` to cycle.	Selection highlights and cursor jumps to each matching keyword.
7. Status Bar	Check status bar while cycling files.	Correct file names, encoding (e.g., `UTF-8 BOM` for `bom_utf8_sample.txt`), line endings (`CRLF` for `crlf_sample.txt`), and syntax names.
8. Git Diffs	Press `Ctrl+D` to enter git mode (if in git repository) or view diff history by pressing `H` (from the tree). Toggle side-by-side diff via the command palette.	Displays diff correctly. Side-by-side mode splits left/right panels.
9. Resizing	Resize the terminal window while running `mantis`.	Viewport adapts immediately without crashing or breaking layout boundary lines.
10. Root Clamp	With the tree focused at the launch directory, press `Backspace`.	No-op; status bar shows `Already at root`.
11. Compare Mode	In a git repo, run `Compare against a revision` from the command palette (`Ctrl+P`), select or type a revision in the picker overlay, press `Enter`.	Tree shows `A`/`M`/`D`/`R` badges; status bar shows a `[compare: <rev>]` badge.
12. Blame Rework	Focus content pane on a tracked file, press `Ctrl+B` for the full blame pane, `B` for the single-line bottom bar.	Blame pane shows hash/author/date/subject columns; bottom bar shows a 2-line summary.
13. Bundled Language Plugins	Press `p` to open the plugin manager, verify `rust`/`python`/`go` are enabled (default).	Folding (`Space`) works on the corresponding language files.
14. Bug Report & Telemetry	Run `Report a bug (save diagnostics locally)` and `Toggle telemetry` from the command palette.	Bug report modal opens with a scrollable diagnostic preview; telemetry toggle shows `telemetry enabled`/`disabled` in the status bar.
15. First-Run Welcome Overlay	Launch `mantis` against a fresh state dir (`MANTIS_STATE_DIR=$(mktemp -d) cargo run -- ./e2e/data`).	A dismissible welcome popup shows 5 essential keybindings; does not reappear after `Esc` and relaunch.

See the per-terminal checklists in e2e/checklists/*.md (section “4. New Features”) for detailed step-by-step coverage of items 10–15.

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