test(prog): cover formatter wiring for python, go, shell, typescript

Four test files plus a shared testutil that locks in the formatter
bindings on C-; f across the four languages. Each test file checks:

- the format command is fboundp after the relevant package loads
- the C-; f binding resolves to that command (in the relevant
  mode-map, or in the buffer-local map for hook-based wiring)
- the underlying executable is on PATH (skipped via ert-skip if
  not installed)

No production change. The bindings were already at C-; f via two
mechanisms. Use-package :bind handles python and shell. The other
two install via local-set-key inside a hook. This regression net
catches silent breakage if any of those wirings get reshaped later.

The shared tests/testutil-format-wiring.el carries
format-test--ensure-packages-init, which calls package-initialize
once per batch run, since make test runs Emacs with --no-site-file
--no-site-lisp. Without it, use-package can't find blacken / shfmt
/ go-mode in elpa/. Also format-test--skip-unless-executable wraps
ert-skip with a clear "not on PATH" message so missing tools fail
informatively.

Per-language wiring inventory (no changes, just locked in):
- Python: blacken-buffer in python-ts-mode-map (use-package :bind)
- Shell: shfmt-buffer in sh-mode-map and bash-ts-mode-map
  (use-package :bind, gated on :if executable-find)
- Go: gofmt via cj/go-mode-keybindings hook
- TS/JS/Web: cj/webdev-format-buffer via cj/webdev-keybindings hook

13 tests across 4 files, all passing.

1 files changed, 44 insertions, 0 deletions

diff --git a/tests/test-prog-webdev--format-wiring.el b/tests/test-prog-webdev--format-wiring.el
new file mode 100644
index 00000000..7d9914f2
--- /dev/null
+++ b/tests/test-prog-webdev--format-wiring.el
@@ -0,0 +1,44 @@
+;;; test-prog-webdev--format-wiring.el --- Verify the TS/JS formatter is wired -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Webdev's binding is installed via `local-set-key' inside the
+;; `cj/webdev-keybindings' hook, fired from typescript-ts-mode,
+;; tsx-ts-mode, js-ts-mode, and web-mode. The format command itself
+;; (`cj/webdev-format-buffer') is defined in prog-webdev.el and shells
+;; out to the `prettier' binary.
+;;
+;; Three checks:
+;;   1. `cj/webdev-format-buffer' is fboundp.
+;;   2. The hook installs C-; f → `cj/webdev-format-buffer' in the
+;;      buffer-local map.
+;;   3. The `prettier' executable is on PATH.
+
+;;; Code:
+
+(require 'ert)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(add-to-list 'load-path (expand-file-name "tests" user-emacs-directory))
+(require 'testutil-format-wiring)
+
+(format-test--ensure-packages-init)
+(ignore-errors (require 'prog-webdev))
+
+(ert-deftest test-prog-webdev-format-command-fboundp ()
+  "Normal: `cj/webdev-format-buffer' is fboundp from prog-webdev."
+  (should (fboundp 'cj/webdev-format-buffer)))
+
+(ert-deftest test-prog-webdev-format-binding-resolves ()
+  "Normal: `cj/webdev-keybindings' installs C-; f → `cj/webdev-format-buffer'."
+  (with-temp-buffer
+    (cj/webdev-keybindings)
+    (should (eq 'cj/webdev-format-buffer
+                (local-key-binding (kbd "C-; f"))))))
+
+(ert-deftest test-prog-webdev-format-executable-on-path ()
+  "Boundary: `prettier' is on PATH (skipped if not installed)."
+  (format-test--skip-unless-executable "prettier")
+  (should (executable-find "prettier")))
+
+(provide 'test-prog-webdev--format-wiring)
+;;; test-prog-webdev--format-wiring.el ends here