test(lsp): narrow startup smoke test for prog-lsp config resolution

Pins the load-time invariants of the central LSP module: lsp-enable-remote stays nil (no auto-start on TRAMP files), the file-watch-ignore defaults live in one idempotent helper, the eldoc provider is stripped from the global hook, and no mode accrues a duplicate lsp-deferred entry. Tests the top-level :init and helper surface, since :config defaults defer to lsp-mode's own load under make test.

1 files changed, 66 insertions, 0 deletions

diff --git a/tests/test-prog-lsp.el b/tests/test-prog-lsp.el
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+;;; test-prog-lsp.el --- Startup smoke test for LSP config resolution -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; A narrow smoke test of prog-lsp.el, the central LSP module.  It pins the
+;; invariants that should hold the moment the config loads, before any server
+;; starts: lsp-enable-remote stays nil (so TRAMP files don't auto-start a slow
+;; LSP), the file-watch-ignore defaults live in one idempotent place, the eldoc
+;; provider is stripped from the global hook, and a mode never accrues a
+;; duplicate lsp-deferred entry.  The generic :config defaults are deferred to
+;; lsp-mode's own load (see the make-test no-package-initialize note in
+;; CLAUDE.md), so this tests the top-level :init and helper surface, which runs.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+(require 'use-package)
+(require 'prog-lsp)
+
+;; lsp-mode's defcustom isn't loaded under make test, and prog-lsp's bare
+;; `(defvar lsp-file-watch-ignored-directories)' only marks it special within
+;; that file's unit.  Declare it special here too so the `let' bindings below
+;; bind dynamically (the helper reads it through the symbol via add-to-list).
+(defvar lsp-file-watch-ignored-directories nil)
+
+(ert-deftest test-prog-lsp-enable-remote-nil ()
+  "Normal: lsp-enable-remote is nil so LSP never auto-starts on TRAMP files."
+  (should (boundp 'lsp-enable-remote))
+  (should (null lsp-enable-remote)))
+
+(ert-deftest test-prog-lsp-file-watch-adds-extras ()
+  "Normal: the build/cache ignore patterns get appended to lsp's watch-ignore list."
+  (let ((lsp-file-watch-ignored-directories '("[/\\\\]\\.git\\'")))
+    (cj/lsp--add-file-watch-ignored-extras)
+    (dolist (pattern cj/lsp-file-watch-ignored-extras)
+      (should (member pattern lsp-file-watch-ignored-directories)))
+    (should (member "[/\\\\]\\.git\\'" lsp-file-watch-ignored-directories))))
+
+(ert-deftest test-prog-lsp-file-watch-idempotent ()
+  "Boundary: adding the extras twice leaves each pattern present exactly once."
+  (let ((lsp-file-watch-ignored-directories '()))
+    (cj/lsp--add-file-watch-ignored-extras)
+    (cj/lsp--add-file-watch-ignored-extras)
+    (dolist (pattern cj/lsp-file-watch-ignored-extras)
+      (should (= 1 (cl-count pattern lsp-file-watch-ignored-directories
+                             :test #'equal))))))
+
+(ert-deftest test-prog-lsp-eldoc-provider-removed-globally ()
+  "Normal: the global eldoc provider is stripped so lsp can't reattach it."
+  (let ((eldoc-documentation-functions
+         (list #'lsp-eldoc-function #'ignore)))
+    (cj/lsp--remove-eldoc-provider-global)
+    (should-not (memq 'lsp-eldoc-function eldoc-documentation-functions))
+    (should (memq 'ignore eldoc-documentation-functions))))
+
+(ert-deftest test-prog-lsp-no-duplicate-mode-hook ()
+  "Boundary: a mode prog-lsp wires never holds more than one lsp-deferred entry.
+prog-lsp and the per-language modules both add lsp-deferred for some modes;
+add-hook dedups identical symbols, and this pins that invariant so a future
+non-symbol (lambda) addition that breaks it gets caught."
+  (dolist (hook '(c-mode-hook python-mode-hook go-ts-mode-hook))
+    (when (boundp hook)
+      (should (>= 1 (cl-count 'lsp-deferred (symbol-value hook)))))))
+
+(provide 'test-prog-lsp)
+;;; test-prog-lsp.el ends here