test(ai-config): cover auth-source, api-key caching, context, clear-buffer

The big-module coverage push starts with ai-config (was 53/191, 27.7%). New test file covers seven helpers that don't depend on a live gptel install:

- `cj/auth-source-secret`: returns string secrets, funcall's function secrets, errors on missing.
- `cj/anthropic-api-key` / `cj/openai-api-key`: cache the result so subsequent calls don't re-hit auth-source.
- `cj/gptel--add-file-to-context`: adds existing files, skips nil and missing paths.
- `cj/gptel-clear-buffer`: erases in a gptel-org buffer and reinserts the fresh prefix; no-ops + messages elsewhere.
- `cj/gptel-context-clear`: three cond branches (`remove-all`, `clear`, alist-fallback) with appropriate `fboundp` stubs.
- `cj/gptel-insert-model-heading`: inserts at the response-begin position with the backend/model heading.

External primitives (`auth-source-search`, `gptel-add-file`, `gptel-context-remove-all`, etc.) are stubbed. The fallback test declares `gptel-context--alist` as a top-level `defvar` so `setq` inside the function reaches the dynamic binding under lexical scoping.

1 files changed, 183 insertions, 0 deletions

diff --git a/tests/test-ai-config-helpers.el b/tests/test-ai-config-helpers.el
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+;;; test-ai-config-helpers.el --- Tests for ai-config helper functions -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Covers helpers that don't depend on a live gptel install:
+;;
+;;   cj/auth-source-secret
+;;   cj/anthropic-api-key   (caching wrapper)
+;;   cj/openai-api-key      (caching wrapper)
+;;   cj/gptel--add-file-to-context
+;;   cj/gptel-clear-buffer
+;;   cj/gptel-context-clear
+;;   cj/gptel-insert-model-heading
+;;
+;; External primitives (`auth-source-search', `gptel-add-file', etc.)
+;; are stubbed so the tests never touch the keyring or the network.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'ai-config)
+
+;; Make `gptel-context--alist' a real dynamic variable for the fallback
+;; test below.  Under lexical-binding a plain `let' is lexical, so the
+;; `setq' inside `cj/gptel-context-clear' would otherwise miss it.
+(defvar gptel-context--alist nil
+  "Dynamic stand-in for the gptel-context alist (gptel not loaded here).")
+
+;;; cj/auth-source-secret
+
+(ert-deftest test-ai-config-auth-source-secret-returns-string ()
+  "Normal: a plain-string secret comes back as-is."
+  (cl-letf (((symbol-function 'auth-source-search)
+             (lambda (&rest _) '((:secret "plaintext")))))
+    (should (equal (cj/auth-source-secret "example.com" "user")
+                   "plaintext"))))
+
+(ert-deftest test-ai-config-auth-source-secret-unwraps-function ()
+  "Normal: a function secret is funcall'd to retrieve the value."
+  (cl-letf (((symbol-function 'auth-source-search)
+             (lambda (&rest _) (list (list :secret (lambda () "called"))))))
+    (should (equal (cj/auth-source-secret "example.com" "user")
+                   "called"))))
+
+(ert-deftest test-ai-config-auth-source-secret-errors-when-missing ()
+  "Error: an empty result raises a clear error."
+  (cl-letf (((symbol-function 'auth-source-search)
+             (lambda (&rest _) nil)))
+    (should-error (cj/auth-source-secret "nope.example.com" "user")
+                  :type 'error)))
+
+;;; cj/anthropic-api-key / cj/openai-api-key
+
+(ert-deftest test-ai-config-anthropic-api-key-caches-after-first-call ()
+  "Normal: a subsequent call returns the cached value without re-fetching."
+  (let ((cj/anthropic-api-key-cached nil)
+        (call-count 0))
+    (cl-letf (((symbol-function 'auth-source-search)
+               (lambda (&rest _)
+                 (cl-incf call-count)
+                 '((:secret "anth-key")))))
+      (should (equal (cj/anthropic-api-key) "anth-key"))
+      (should (equal (cj/anthropic-api-key) "anth-key"))
+      (should (= call-count 1)))))
+
+(ert-deftest test-ai-config-openai-api-key-caches-after-first-call ()
+  "Normal: same caching contract as the anthropic key."
+  (let ((cj/openai-api-key-cached nil)
+        (call-count 0))
+    (cl-letf (((symbol-function 'auth-source-search)
+               (lambda (&rest _)
+                 (cl-incf call-count)
+                 '((:secret "oai-key")))))
+      (should (equal (cj/openai-api-key) "oai-key"))
+      (should (equal (cj/openai-api-key) "oai-key"))
+      (should (= call-count 1)))))
+
+;;; cj/gptel--add-file-to-context
+
+(ert-deftest test-ai-config-add-file-to-context-adds-existing-file ()
+  "Normal: an existing file is added and the function returns t."
+  (let ((tmp (make-temp-file "ai-config-add-file-")))
+    (unwind-protect
+        (let ((gptel-context--alist nil)
+              (added nil))
+          (cl-letf (((symbol-function 'gptel-add-file)
+                     (lambda (f) (setq added f)))
+                    ((symbol-function 'message) #'ignore))
+            (should (eq (cj/gptel--add-file-to-context tmp) t))
+            (should (equal added tmp))))
+      (delete-file tmp))))
+
+(ert-deftest test-ai-config-add-file-to-context-skips-missing-file ()
+  "Boundary: a non-existent path returns nil and doesn't call gptel-add-file."
+  (let ((called nil))
+    (cl-letf (((symbol-function 'gptel-add-file)
+               (lambda (_) (setq called t))))
+      (should-not (cj/gptel--add-file-to-context "/no/such/path"))
+      (should-not called))))
+
+(ert-deftest test-ai-config-add-file-to-context-skips-nil-path ()
+  "Boundary: a nil path returns nil without calling gptel-add-file."
+  (let ((called nil))
+    (cl-letf (((symbol-function 'gptel-add-file)
+               (lambda (_) (setq called t))))
+      (should-not (cj/gptel--add-file-to-context nil))
+      (should-not called))))
+
+;;; cj/gptel-clear-buffer
+
+(ert-deftest test-ai-config-clear-buffer-erases-in-gptel-org-buffer ()
+  "Normal: a gptel-mode org buffer is erased and the fresh org prefix is reinserted."
+  (with-temp-buffer
+    (delay-mode-hooks (org-mode))
+    (setq-local gptel-mode t)
+    (insert "* Existing conversation\nstuff\n")
+    (let ((msg nil))
+      (cl-letf (((symbol-function 'message)
+                 (lambda (fmt &rest args)
+                   (setq msg (apply #'format fmt args)))))
+        (cj/gptel-clear-buffer))
+      (should (string-match-p "cleared" msg)))
+    ;; The fresh prefix is an org heading starting with "* ".
+    (should (string-prefix-p "* " (buffer-string)))
+    (should-not (string-match-p "Existing conversation" (buffer-string)))))
+
+(ert-deftest test-ai-config-clear-buffer-noop-when-not-gptel-org ()
+  "Boundary: in a non-gptel buffer the function messages and changes nothing."
+  (with-temp-buffer
+    (insert "untouched\n")
+    (let ((msg nil))
+      (cl-letf (((symbol-function 'message)
+                 (lambda (fmt &rest args)
+                   (setq msg (apply #'format fmt args)))))
+        (cj/gptel-clear-buffer))
+      (should (string-match-p "Not a GPTel buffer" msg))
+      (should (equal (buffer-string) "untouched\n")))))
+
+;;; cj/gptel-context-clear
+
+(ert-deftest test-ai-config-context-clear-uses-remove-all-when-available ()
+  "Normal: when `gptel-context-remove-all' is bound, it wins the cond.
+The stub must be a command because `cj/gptel-context-clear' invokes it
+via `call-interactively'."
+  (let ((called nil)
+        (msg nil))
+    (cl-letf (((symbol-function 'gptel-context-remove-all)
+               (lambda () (interactive) (setq called 'remove-all)))
+              ((symbol-function 'message)
+               (lambda (fmt &rest args) (setq msg (apply #'format fmt args)))))
+      (cj/gptel-context-clear))
+    (should (eq called 'remove-all))
+    (should (string-match-p "cleared" msg))))
+
+(ert-deftest test-ai-config-context-clear-falls-back-to-alist-setq ()
+  "Boundary: when no clearing function exists, the alist is set to nil."
+  (let ((gptel-context--alist '((:dummy)))
+        (msg nil))
+    (cl-letf (((symbol-function 'fboundp)
+               (lambda (sym)
+                 (not (memq sym '(gptel-context-remove-all gptel-context-clear)))))
+              ((symbol-function 'message)
+               (lambda (fmt &rest args) (setq msg (apply #'format fmt args)))))
+      (cj/gptel-context-clear))
+    (should (null gptel-context--alist))
+    (should (string-match-p "cleared" msg))))
+
+;;; cj/gptel-insert-model-heading
+
+(ert-deftest test-ai-config-insert-model-heading-inserts-at-given-position ()
+  "Normal: an Org heading is inserted at RESPONSE-BEGIN-POS."
+  (with-temp-buffer
+    (insert "response text")
+    (cl-letf (((symbol-function 'cj/gptel-backend-and-model)
+               (lambda () "Anthropic: claude-test [2026-05-13 12:00:00]")))
+      (cj/gptel-insert-model-heading (point-min) (point-max)))
+    (should (string-prefix-p "* Anthropic: claude-test" (buffer-string)))
+    (should (string-match-p "\nresponse text" (buffer-string)))))
+
+(provide 'test-ai-config-helpers)
+;;; test-ai-config-helpers.el ends here