t4208: abstract away SHA-1-specific constants

diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index dc98b4bc6dc7aab41eca38d9e1086ad2b6701fd3..f6dc05654ea5a2f06b41d8c300f8916b2e773972 100755 (executable)
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -6,7 +6,7 @@
 test_description='Test git update-ref and basic ref logging'
 . ./test-lib.sh
 
-Z=$_z40
+Z=$ZERO_OID
 
 m=refs/heads/master
 n_dir=refs/heads/gu
@@ -1253,7 +1253,10 @@ run_with_limited_open_files () {
        (ulimit -n 32 && "$@")
 }
 
-test_lazy_prereq ULIMIT_FILE_DESCRIPTORS 'run_with_limited_open_files true'
+test_lazy_prereq ULIMIT_FILE_DESCRIPTORS '
+       test_have_prereq !MINGW,!CYGWIN &&
+       run_with_limited_open_files true
+'
 
 test_expect_success ULIMIT_FILE_DESCRIPTORS 'large transaction creating branches does not burst open file limit' '
 (