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, 88 insertions, 0 deletions

diff --git a/tests/test-gloss-fetch--multi-source-walks-registry.el b/tests/test-gloss-fetch--multi-source-walks-registry.el
new file mode 100644
index 0000000..fe04e02
--- /dev/null
+++ b/tests/test-gloss-fetch--multi-source-walks-registry.el
@@ -0,0 +1,88 @@
+;;; test-gloss-fetch--multi-source-walks-registry.el --- Registry walk tests -*- lexical-binding: t -*-
+
+;; SPDX-License-Identifier: GPL-3.0-or-later
+
+;;; Commentary:
+;; `gloss-fetch--sources' is an alist (source-symbol → fetcher fn).
+;; `gloss-fetch-sources' is the user-facing defcustom that orders the
+;; walk.  Each fetcher returns a per-source result plist.  The walker
+;; aggregates results across all configured sources.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+(require 'gloss-fetch)
+
+(ert-deftest test-gloss-fetch-collect-walks-registry-in-defcustom-order ()
+  "Normal: walker visits each source in `gloss-fetch-sources' order, gathers a result per source."
+  (let* ((calls nil)
+         (gloss-fetch--sources
+          `((alpha . ,(lambda (term)
+                        (push 'alpha calls)
+                        (list :source 'alpha :status :ok :defs
+                              (list (list :source 'alpha :text (concat "A:" term))))))
+            (beta . ,(lambda (term)
+                       (push 'beta calls)
+                       (list :source 'beta :status :no-defs
+                             :reason (concat "no entry for " term))))))
+         (gloss-fetch-sources '(alpha beta))
+         (per-source (gloss-fetch--collect "x")))
+    (should (equal (reverse calls) '(alpha beta)))
+    (should (= 2 (length per-source)))
+    (should (eq 'alpha (plist-get (nth 0 per-source) :source)))
+    (should (eq 'beta  (plist-get (nth 1 per-source) :source)))))
+
+(ert-deftest test-gloss-fetch-rollup-mixes-no-defs-and-failed ()
+  "Boundary: a mix of :no-defs and :server-error rolls up with both lists populated."
+  (let* ((gloss-fetch--sources
+          `((alpha . ,(lambda (_term)
+                        (list :source 'alpha :status :no-defs :reason "404")))
+            (beta . ,(lambda (_term)
+                       (list :source 'beta :status :server-error :reason "HTTP 503")))))
+         (gloss-fetch-sources '(alpha beta))
+         (result (gloss-fetch-definitions "x")))
+    (should (eq (car result) :empty))
+    (should (member 'alpha (plist-get result :no-defs)))
+    (should (member 'beta (plist-get result :failed)))))
+
+(ert-deftest test-gloss-fetch-rollup-any-ok-yields-ok ()
+  "Boundary: if any source returns :ok with defs, the rollup is (:ok DEFS)."
+  (let* ((gloss-fetch--sources
+          `((alpha . ,(lambda (_term)
+                        (list :source 'alpha :status :no-defs :reason "404")))
+            (beta . ,(lambda (_term)
+                       (list :source 'beta :status :ok :defs
+                             (list (list :source 'beta :text "got it")))))))
+         (gloss-fetch-sources '(alpha beta))
+         (result (gloss-fetch-definitions "x")))
+    (should (eq (car result) :ok))
+    (should (= 1 (length (plist-get result :ok))))
+    (should (equal "got it" (plist-get (car (plist-get result :ok)) :text)))))
+
+(ert-deftest test-gloss-fetch-collect-skips-source-not-in-defcustom ()
+  "Error: a source registered in `gloss-fetch--sources' but not in `gloss-fetch-sources' is skipped."
+  (let* ((called nil)
+         (gloss-fetch--sources
+          `((alpha . ,(lambda (_term)
+                        (setq called t)
+                        (list :source 'alpha :status :ok :defs
+                              (list (list :source 'alpha :text "x")))))))
+         (gloss-fetch-sources '()) ; empty — skip everything
+         (per-source (gloss-fetch--collect "x")))
+    (should-not called)
+    (should (null per-source))))
+
+(ert-deftest test-gloss-fetch-collect-skips-unknown-source-symbol ()
+  "Error: a symbol in `gloss-fetch-sources' with no registered fetcher is silently skipped."
+  (let* ((gloss-fetch--sources
+          `((alpha . ,(lambda (_term)
+                        (list :source 'alpha :status :ok :defs
+                              (list (list :source 'alpha :text "x")))))))
+         (gloss-fetch-sources '(zeta alpha))
+         (per-source (gloss-fetch--collect "x")))
+    (should (= 1 (length per-source)))
+    (should (eq 'alpha (plist-get (car per-source) :source)))))
+
+(provide 'test-gloss-fetch--multi-source-walks-registry)
+;;; test-gloss-fetch--multi-source-walks-registry.el ends here