test-lib: provide case insensitivity as a prerequisite

Case insensitivity plays a role in several tests and is tested in several
tests. Therefore, move the test from t003 into the test lib and use the
prerequisite in t0003.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/README

@@ -625,6 +625,10 @@ use these, and "test_set_prereq" for how to define your own.
    Git was compiled with USE_LIBPCRE=YesPlease. Wrap any tests
    that use git-grep --perl-regexp or git-grep -P in these.
 
+ - CASE_INSENSITIVE_FS
+
+   Test is run on a case insensitive file system.
+
 Tips for Writing Tests
 ----------------------
 

t/t0003-attributes.sh

@@ -123,16 +123,6 @@ test_expect_success 'attribute matching is case insensitive when core.ignorecase
 
 '
 
-test_expect_success 'check whether FS is case-insensitive' '
-	mkdir junk &&
-	echo good >junk/CamelCase &&
-	echo bad >junk/camelcase &&
-	if test "$(cat junk/CamelCase)" != good
-	then
-		test_set_prereq CASE_INSENSITIVE_FS
-	fi
-'
-
 test_expect_success CASE_INSENSITIVE_FS 'additional case insensitivity tests' '
 	test_must_fail attr_check a/B/D/g "a/b/d/*" "-c core.ignorecase=0" &&
 	test_must_fail attr_check A/B/D/NO "a/b/d/*" "-c core.ignorecase=0" &&

t/test-lib.sh

@@ -664,6 +664,12 @@ test_lazy_prereq SYMLINKS '
 	ln -s x y && test -h y
 '
 
+test_lazy_prereq CASE_INSENSITIVE_FS '
+	echo good >CamelCase &&
+	echo bad >camelcase &&
+	test "$(cat CamelCase)" != good
+'
+
 # When the tests are run as root, permission tests will report that
 # things are writable when they shouldn't be.
 test -w / || test_set_prereq SANITY