refactor(dirvish): extract cj/--html-file-p; match HTML case-insensitively

`cj/dirvish-open-html-in-eww' inlined a `string-match-p' against `\.html?\=' to decide whether to hand a file to eww.  The check was case-sensitive, so `.HTML' fell through to the "Not an HTML file" message even though every browser treats it as HTML.  Lift the predicate into `cj/--html-file-p' and bind `case-fold-search' to t so uppercase and mixed-case extensions match.  The trailing-`\=' anchor stays so files like `html-thing.org' still don't match.

Seven Normal/Boundary/Error tests cover lowercase `.html', `.htm', uppercase `.HTML', mixed-case `.Html', embedded `html' (no match), non-html extensions (no match), and no-extension files (no match).

1 files changed, 53 insertions, 0 deletions

diff --git a/tests/test-dirvish-config-html-file-p.el b/tests/test-dirvish-config-html-file-p.el
new file mode 100644
index 00000000..dd18edaf
--- /dev/null
+++ b/tests/test-dirvish-config-html-file-p.el
@@ -0,0 +1,53 @@
+;;; test-dirvish-config-html-file-p.el --- Tests for the html-file predicate -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; `cj/--html-file-p' is the predicate behind `cj/dirvish-open-html-in-eww'.
+;; The earlier inline regex was case-sensitive (`.html?\='), but most
+;; browsers treat `.HTML' as HTML too, so the helper is case-insensitive.
+;; The predicate also anchors on the trailing extension so files with
+;; "html" embedded in the middle of the name don't match.
+
+;;; Code:
+
+(require 'ert)
+(require 'package)
+
+(setq package-user-dir (expand-file-name "elpa" user-emacs-directory))
+(package-initialize)
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(add-to-list 'load-path (expand-file-name "elpa/dirvish-2.3.0/extensions"
+                                          user-emacs-directory))
+(require 'user-constants)
+(require 'keybindings)
+(require 'dirvish-config)
+
+(ert-deftest test-cj--html-file-p-html-extension-matches ()
+  "Normal: `.html' extension matches."
+  (should (cj/--html-file-p "/tmp/index.html")))
+
+(ert-deftest test-cj--html-file-p-htm-extension-matches ()
+  "Normal: `.htm' extension matches (legacy 8.3 form)."
+  (should (cj/--html-file-p "/tmp/page.htm")))
+
+(ert-deftest test-cj--html-file-p-uppercase-html-matches ()
+  "Boundary: `.HTML' (uppercase) matches -- match is case-insensitive."
+  (should (cj/--html-file-p "/tmp/index.HTML")))
+
+(ert-deftest test-cj--html-file-p-mixed-case-html-matches ()
+  "Boundary: mixed case (`.Html') matches."
+  (should (cj/--html-file-p "/tmp/index.Html")))
+
+(ert-deftest test-cj--html-file-p-embedded-html-does-not-match ()
+  "Boundary: `html' in the middle of the name doesn't match (anchor at end)."
+  (should-not (cj/--html-file-p "/tmp/html-thing.org")))
+
+(ert-deftest test-cj--html-file-p-non-html-extension-does-not-match ()
+  "Error: a non-html file returns nil."
+  (should-not (cj/--html-file-p "/tmp/notes.txt")))
+
+(ert-deftest test-cj--html-file-p-no-extension-does-not-match ()
+  "Boundary: a file without an extension does not match."
+  (should-not (cj/--html-file-p "/tmp/README")))
+
+(provide 'test-dirvish-config-html-file-p)
+;;; test-dirvish-config-html-file-p.el ends here