fetch tests: add a test for clobbering tag behavior

diff --git a/t/test-lib.sh b/t/test-lib.sh
index ea2bbaaa7ab4dc77d0ef13cafbe45d1b12bd67e8..28315706be709d28c85785e389b381a8617337e3 100644 (file)
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -184,6 +184,8 @@ _x40="$_x35$_x05"
 # Zero SHA-1
 _z40=0000000000000000000000000000000000000000
 
+OID_REGEX="$_x40"
+ZERO_OID=$_z40
 EMPTY_TREE=4b825dc642cb6eb9a060e54bf8d69288fbee4904
 EMPTY_BLOB=e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
 
@@ -195,7 +197,7 @@ LF='
 # when case-folding filenames
 u200c=$(printf '\342\200\214')
 
-export _x05 _x35 _x40 _z40 LF u200c EMPTY_TREE EMPTY_BLOB
+export _x05 _x35 _x40 _z40 LF u200c EMPTY_TREE EMPTY_BLOB ZERO_OID OID_REGEX
 
 # Each test should start with something like this, after copyright notices:
 #
@@ -1106,12 +1108,7 @@ test_lazy_prereq UTF8_NFD_TO_NFC '
        auml=$(printf "\303\244")
        aumlcdiar=$(printf "\141\314\210")
        >"$auml" &&
-       case "$(echo *)" in
-       "$aumlcdiar")
-               true ;;
-       *)
-               false ;;
-       esac
+       test -f "$aumlcdiar"
 '
 
 test_lazy_prereq AUTOIDENT '
@@ -1212,3 +1209,10 @@ test_lazy_prereq TIME_T_IS_64BIT 'test-tool date time_t-is64bit'
 test_lazy_prereq CURL '
        curl --version
 '
+
+# SHA1 is a test if the hash algorithm in use is SHA-1.  This is both for tests
+# which will not work with other hash algorithms and tests that work but don't
+# test anything meaningful (e.g. special values which cause short collisions).
+test_lazy_prereq SHA1 '
+       test $(git hash-object /dev/null) = e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
+'