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, 46 insertions, 0 deletions

diff --git a/tests/test-prog-go--format-wiring.el b/tests/test-prog-go--format-wiring.el
new file mode 100644
index 00000000..99d80772
--- /dev/null
+++ b/tests/test-prog-go--format-wiring.el
@@ -0,0 +1,46 @@
+;;; test-prog-go--format-wiring.el --- Verify the Go formatter is wired -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Go's binding is installed via `local-set-key' inside the
+;; `cj/go-mode-keybindings' hook, not via use-package's `:bind'. The
+;; test runs the hook directly in a temp buffer and asks the buffer-
+;; local map what C-; f resolves to.
+;;
+;; Three checks:
+;;   1. `gofmt' is fboundp after go-mode loads.
+;;   2. The hook installs C-; f → `gofmt' in the buffer-local map.
+;;   3. `gofmt' (or `goimports') 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-go))
+(require 'go-mode)
+
+(ert-deftest test-prog-go-format-command-fboundp ()
+  "Normal: `gofmt' is fboundp after `go-mode' loads."
+  (should (fboundp 'gofmt)))
+
+(ert-deftest test-prog-go-format-binding-resolves ()
+  "Normal: `cj/go-mode-keybindings' installs C-; f → `gofmt' locally."
+  (with-temp-buffer
+    (cj/go-mode-keybindings)
+    (should (eq 'gofmt (local-key-binding (kbd "C-; f"))))))
+
+(ert-deftest test-prog-go-format-executable-on-path ()
+  "Boundary: `gofmt' or `goimports' is on PATH (skipped if neither installed).
+The Go config sets `gofmt-command' to \"goimports\" but falls back to
+plain `gofmt' if goimports isn't installed."
+  (unless (or (executable-find "gofmt") (executable-find "goimports"))
+    (ert-skip "Neither gofmt nor goimports on PATH"))
+  (should (or (executable-find "gofmt")
+              (executable-find "goimports"))))
+
+(provide 'test-prog-go--format-wiring)
+;;; test-prog-go--format-wiring.el ends here