Add new function `lm-package-needs-footer-line`

* lisp/emacs-lisp/lisp-mnt.el (lm-package-needs-footer-line):
Factor out new function...
* lisp/emacs-lisp/package.el (package-buffer-info): ...from here.
* lisp/emacs-lisp/lisp-mnt.el (lm-verify): Use above new function.
* test/lisp/emacs-lisp/lisp-mnt-tests.el
(lm-tests--lm-package-needs-footer-line/empty-dependencies)
(lm-tests--lm-package-needs-footer-line/old-version)
(lm-tests--lm-package-needs-footer-line/new-version):
New tests.

1 files changed, 13 insertions, 0 deletions

diff --git a/test/lisp/emacs-lisp/lisp-mnt-tests.el b/test/lisp/emacs-lisp/lisp-mnt-tests.el
index e32480ada46..147062cba29 100644
--- a/test/lisp/emacs-lisp/lisp-mnt-tests.el
+++ b/test/lisp/emacs-lisp/lisp-mnt-tests.el
@@ -49,6 +49,19 @@
                      (project "0.9.8") (xref "1.6.2") (eldoc "1.14.0")
                      (seq "2.23") (external-completion "0.1"))))))
 
+(ert-deftest lm-tests--lm-package-needs-footer-line/empty-dependencies ()
+  (with-temp-buffer
+    (should (lm-package-needs-footer-line))))
+
+(ert-deftest lm-tests--lm-package-needs-footer-line/old-version ()
+  (with-temp-buffer
+    (insert ";; Package-Requires: ((emacs \"29.1\"))\n")
+    (should (lm-package-needs-footer-line))))
+
+(ert-deftest lm-tests--lm-package-needs-footer-line/new-version ()
+  (with-temp-buffer
+    (insert ";; Package-Requires: ((emacs \"30.1\"))\n")
+    (should (not (lm-package-needs-footer-line)))))
 
 (ert-deftest lm--tests-lm-website ()
   (with-temp-buffer