In order to get the ERT tests to pass on my system, I need to disable the
following three tests:

--- i/test/lisp/eshell/em-ls-tests.el
+++ w/test/lisp/eshell/em-ls-tests.el
@@ -77,6 +77,7 @@

 (ert-deftest em-ls-test-bug27844 ()
   "Test for https://debbugs.gnu.org/27844 ."
+  (skip-unless (not (eq system-type 'darwin)))
   (let ((orig eshell-ls-use-in-dired)
         (dired-use-ls-dired 'unspecified)
         buf insert-directory-program)
--- i/test/lisp/net/tramp-tests.el
+++ w/test/lisp/net/tramp-tests.el
@@ -3636,6 +3636,7 @@ tramp--test-shell-command-to-string-asynchronously
 ;; This test is inspired by Bug#27009.
 (ert-deftest tramp-test32-environment-variables-and-port-numbers ()
   "Check that two connections with separate ports are different."
+  (skip-unless (not (eq system-type 'darwin)))
   (skip-unless (tramp--test-enabled))
   ;; We test it only for the mock-up connection; otherwise there might
   ;; be problems with the used ports.
--- i/test/src/fileio-tests.el
+++ w/test/src/fileio-tests.el
@@ -48,7 +48,7 @@ fileio-tests--symlink-failure
   ;; Some Windows versions don't support symlinks, and those which do
   ;; will pop up UAC elevation prompts, so we disable this test on
   ;; MS-Windows.
-  (skip-unless (not (eq system-type 'windows-nt)))
+  (skip-unless (not (memq system-type '(darwin windows-nt))))
   (should (equal nil (fileio-tests--symlink-failure))))

 (ert-deftest fileio-tests--directory-file-name ()

-- 
John Wiegley                  GPG fingerprint = 4710 CF98 AF9B 327B B80F
http://newartisans.com                          60E1 46C4 BD1A 7AC1 4BA2