t0060: verify that real_path() works correctly with absolute paths

There is currently a bug: if passed an absolute top-level path that
doesn't exist (e.g., "/foo") it incorrectly interprets the path as a
relative path (e.g., returns "$(pwd)/foo").  So mark the test as
failing.

These tests are skipped on Windows because test-path-utils operates on
a DOS-style absolute path even if a POSIX style absolute path is
passed as argument.

Adjusted for Windows by: Johannes Sixt <j6t@kdbg.org>

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t0060-path-utils.sh

@@ -148,7 +148,17 @@ test_expect_success 'real path rejects the empty string' '
 	test_must_fail test-path-utils real_path ""
 '
 
-test_expect_success SYMLINKS 'real path works as expected' '
+test_expect_failure POSIX 'real path works on absolute paths' '
+	nopath="hopefully-absent-path" &&
+	test "/" = "$(test-path-utils real_path "/")" &&
+	test "/$nopath" = "$(test-path-utils real_path "/$nopath")" &&
+	# Find an existing top-level directory for the remaining tests:
+	d=$(pwd -P | sed -e "s|^\([^/]*/[^/]*\)/.*|\1|") &&
+	test "$d" = "$(test-path-utils real_path "$d")" &&
+	test "$d/$nopath" = "$(test-path-utils real_path "$d/$nopath")"
+'
+
+test_expect_success SYMLINKS 'real path works on symlinks' '
 	mkdir first &&
 	ln -s ../.git first/.git &&
 	mkdir second &&