[PATCH 4/7] t0013: do not skip the entire file wholesale without DC_SHA1

[Johannes Schindelin <johannes.schindelin@gmx.de>]

So far, there is only one test case in that script, and that case indeed
requires that the code was compiled with with the DC_SHA1 flag.

However, we are about to add another test case to verify that the
DC_AND_OPENSSL_SHA1 flag works correctly, too.

So let's refactor the code a little.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 t/t0013-sha1dc.sh | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/t/t0013-sha1dc.sh b/t/t0013-sha1dc.sh
index 6d655cb161b..435a96d6108 100755
--- a/t/t0013-sha1dc.sh
+++ b/t/t0013-sha1dc.sh
@@ -4,13 +4,9 @@ test_description='test sha1 collision detection'
 . ./test-lib.sh
 TEST_DATA="$TEST_DIRECTORY/t0013"
 
-if test -z "$DC_SHA1"
-then
-	skip_all='skipping sha1 collision tests, DC_SHA1 not set'
-	test_done
-fi
+test -z "$DC_SHA1" || test_set_prereq DC_SHA1
 
-test_expect_success 'test-sha1 detects shattered pdf' '
+test_expect_success DC_SHA1 'test-sha1 detects shattered pdf' '
 	test_must_fail test-sha1 <"$TEST_DATA/shattered-1.pdf" 2>err &&
 	test_i18ngrep collision err &&
 	grep 38762cf7f55934b34d179ae6a4c80cadccbb7f0a err
-- 
2.12.1.windows.1