test: add gloss-fetch test suite (red phase)

Eight test files cover the network layer's public and internal contract.
The boundary mock is `url-retrieve-synchronously', wrapped by a small
`testutil-gloss-fetch' helper that builds response buffers in the shape
the url library returns.

Tests cover the 200 happy paths (anaphora and SBIR fixtures), 404 to
:no-defs, 5xx and 4xx-other and malformed JSON to :server-error, 429 to
:rate-limited, nil-from-url to :unreachable, the libxml availability
probe (one-shot, signals user-error when absent), the registry walker
ordering, and the pure HTML strip helper across N/B/E.

Tests fail on missing `gloss-fetch--*' functions, as expected for red
phase.

1 files changed, 48 insertions, 0 deletions

diff --git a/tests/testutil-gloss-fetch.el b/tests/testutil-gloss-fetch.el
new file mode 100644
index 0000000..a144d91
--- /dev/null
+++ b/tests/testutil-gloss-fetch.el
@@ -0,0 +1,48 @@
+;;; testutil-gloss-fetch.el --- Test helpers for gloss-fetch -*- lexical-binding: t -*-
+
+;; SPDX-License-Identifier: GPL-3.0-or-later
+
+;;; Commentary:
+
+;; Helpers for tests that exercise `gloss-fetch'.  The boundary mock is
+;; `url-retrieve-synchronously', so these helpers build response buffers
+;; in the shape Emacs's url library returns: status line, blank line,
+;; body.  The body comes from a JSON fixture loaded via
+;; `gloss-test--load-wiktionary-fixture' (provided by testutil-gloss.el
+;; on a parallel branch).
+
+;;; Code:
+
+(defun gloss-fetch-test--make-response-buffer (status-line body)
+  "Return a fresh buffer containing STATUS-LINE, a blank line, and BODY.
+STATUS-LINE is an HTTP status line such as \"HTTP/1.1 200 OK\".  BODY
+is the response body as a string.  The buffer is unibyte so that
+multibyte handling is exercised end-to-end."
+  (let ((buf (generate-new-buffer " *gloss-fetch-test-response*")))
+    (with-current-buffer buf
+      (set-buffer-multibyte nil)
+      (insert status-line "\n")
+      (insert "Content-Type: application/json\n")
+      (insert "\n")
+      (insert (encode-coding-string (or body "") 'utf-8)))
+    buf))
+
+(defmacro gloss-fetch-test--with-mocked-url (response-fn &rest body)
+  "Run BODY with `url-retrieve-synchronously' replaced by RESPONSE-FN.
+RESPONSE-FN takes the URL string and returns either a buffer (the
+response) or nil (to simulate timeout / unreachable)."
+  (declare (indent 1) (debug t))
+  `(cl-letf (((symbol-function 'url-retrieve-synchronously)
+              (lambda (url &rest _args) (funcall ,response-fn url))))
+     ,@body))
+
+(defun gloss-fetch-test--ok-response (body)
+  "Return a 200 OK response buffer with BODY."
+  (gloss-fetch-test--make-response-buffer "HTTP/1.1 200 OK" body))
+
+(defun gloss-fetch-test--status-response (status-line &optional body)
+  "Return a response buffer with STATUS-LINE and optional BODY (default empty)."
+  (gloss-fetch-test--make-response-buffer status-line (or body "")))
+
+(provide 'testutil-gloss-fetch)
+;;; testutil-gloss-fetch.el ends here