test-lib: use 'test ...' instead of '[ ... ]'

(see Documentation/CodingGuidelines)

Signed-off-by: Richard Hansen <rhansen@bbn.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/test-lib.sh

@@ -184,10 +184,10 @@ export _x05 _x40 _z40 LF u200c
 # This test checks if command xyzzy does the right thing...
 # '
 # . ./test-lib.sh
-[ "x$ORIGINAL_TERM" != "xdumb" ] && (
+test "x$ORIGINAL_TERM" != "xdumb" && (
 		TERM=$ORIGINAL_TERM &&
 		export TERM &&
-		[ -t 1 ] &&
+		test -t 1 &&
 		tput bold >/dev/null 2>&1 &&
 		tput setaf 1 >/dev/null 2>&1 &&
 		tput sgr0 >/dev/null 2>&1
@@ -684,7 +684,7 @@ test_done () {
 		then
 			error "Can't use skip_all after running some tests"
 		fi
-		[ -z "$skip_all" ] || skip_all=" # SKIP $skip_all"
+		test -z "$skip_all" || skip_all=" # SKIP $skip_all"
 
 		if test $test_external_has_tap -eq 0
 		then