test(flyspell-abbrev): cover checker gate, overlay search, mode dispatch

flyspell-and-abbrev.el had no tests. I added eight: cj/--require-spell-checker (errors when no checker is on PATH, passes when one is), cj/find-previous-flyspell-overlay against synthetic overlays (finds the closest previous flyspell overlay, ignores non-flyspell ones, returns nil when none exist), and cj/flyspell-on-for-buffer-type dispatching to flyspell-prog-mode in code buffers and flyspell-mode in text buffers.

I left cj/flyspell-then-abbrev to manual testing. Pinning its flyspell-UI orchestration would mean mocking flyspell internals rather than our own logic.

1 files changed, 101 insertions, 0 deletions

diff --git a/tests/test-flyspell-and-abbrev.el b/tests/test-flyspell-and-abbrev.el
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+;;; test-flyspell-and-abbrev.el --- Tests for flyspell-and-abbrev.el -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Coverage for the testable seams in flyspell-and-abbrev.el:
+;;
+;; - `cj/--require-spell-checker' (executable-find gate, mocked PATH)
+;; - `cj/find-previous-flyspell-overlay' (overlay sort + flyspell/face filter,
+;;   exercised against synthetic overlays so no aspell is needed)
+;; - `cj/flyspell-on-for-buffer-type' (prog-mode vs text-mode dispatch, with
+;;   the flyspell entry points mocked)
+;;
+;; `cj/flyspell-then-abbrev' is left to manual testing — it orchestrates
+;; flyspell's interactive correction UI, and pinning it would mean mocking
+;; flyspell internals rather than testing our logic.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+(require 'flyspell)
+(require 'flyspell-and-abbrev)
+
+(defun test-flyspell--make-incorrect-overlay (beg end)
+  "Make a flyspell `incorrect' overlay spanning BEG..END in the current buffer."
+  (let ((o (make-overlay beg end)))
+    (overlay-put o 'flyspell-overlay t)
+    (overlay-put o 'face 'flyspell-incorrect)
+    o))
+
+;; ------------------------ cj/--require-spell-checker -------------------------
+
+(ert-deftest test-flyspell-require-spell-checker-present ()
+  "Normal: a checker on PATH means no error."
+  (cl-letf (((symbol-function 'executable-find)
+             (lambda (cmd) (equal cmd (car cj/--spell-checker-executables)))))
+    (should-not (cj/--require-spell-checker))))
+
+(ert-deftest test-flyspell-require-spell-checker-missing ()
+  "Error: no checker on PATH signals user-error."
+  (cl-letf (((symbol-function 'executable-find) (lambda (_) nil)))
+    (should-error (cj/--require-spell-checker) :type 'user-error)))
+
+;; --------------------- cj/find-previous-flyspell-overlay ---------------------
+
+(ert-deftest test-flyspell-find-previous-overlay-returns-start ()
+  "Normal: a flyspell overlay before POSITION returns its start position."
+  (with-temp-buffer
+    (insert "hello world")
+    (test-flyspell--make-incorrect-overlay 1 6)
+    (should (= (cj/find-previous-flyspell-overlay (point-max)) 1))))
+
+(ert-deftest test-flyspell-find-previous-overlay-picks-closest ()
+  "Normal: with several, the closest overlay before POSITION wins."
+  (with-temp-buffer
+    (insert "alpha beta gamma delta")
+    (test-flyspell--make-incorrect-overlay 1 6)    ; alpha
+    (test-flyspell--make-incorrect-overlay 12 17)  ; gamma
+    (should (= (cj/find-previous-flyspell-overlay (point-max)) 12))))
+
+(ert-deftest test-flyspell-find-previous-overlay-none ()
+  "Boundary: no overlays at all yields nil."
+  (with-temp-buffer
+    (insert "nothing flagged here")
+    (should-not (cj/find-previous-flyspell-overlay (point-max)))))
+
+(ert-deftest test-flyspell-find-previous-overlay-skips-non-flyspell ()
+  "Boundary: an overlay without the flyspell marker is ignored."
+  (with-temp-buffer
+    (insert "plain overlay text")
+    (let ((o (make-overlay 1 6)))
+      (overlay-put o 'face 'flyspell-incorrect)) ; face but not a flyspell overlay
+    (should-not (cj/find-previous-flyspell-overlay (point-max)))))
+
+;; --------------------- cj/flyspell-on-for-buffer-type ------------------------
+
+(ert-deftest test-flyspell-on-for-buffer-type-prog-mode ()
+  "Normal: in a prog-mode buffer, flyspell-prog-mode is used."
+  (let (prog-called)
+    (cl-letf (((symbol-function 'flyspell-prog-mode) (lambda () (setq prog-called t)))
+              ((symbol-function 'flyspell-mode)
+               (lambda (&rest _) (error "flyspell-mode should not run in prog-mode")))
+              ((symbol-function 'flyspell-buffer) #'ignore))
+      (with-temp-buffer
+        (emacs-lisp-mode)
+        (cj/flyspell-on-for-buffer-type)))
+    (should prog-called)))
+
+(ert-deftest test-flyspell-on-for-buffer-type-text-mode ()
+  "Normal: in a text-mode buffer, flyspell-mode is used."
+  (let (mode-called)
+    (cl-letf (((symbol-function 'flyspell-mode) (lambda (&rest _) (setq mode-called t)))
+              ((symbol-function 'flyspell-prog-mode)
+               (lambda () (error "flyspell-prog-mode should not run in text-mode")))
+              ((symbol-function 'flyspell-buffer) #'ignore))
+      (with-temp-buffer
+        (text-mode)
+        (cj/flyspell-on-for-buffer-type)))
+    (should mode-called)))
+
+(provide 'test-flyspell-and-abbrev)
+;;; test-flyspell-and-abbrev.el ends here