diff --git a/t/t1003-read-tree-prefix.sh b/t/t1003-read-tree-prefix.sh
index 48ab117d75..1c595f18bb 100755
--- a/t/t1003-read-tree-prefix.sh
+++ b/t/t1003-read-tree-prefix.sh
@@ -8,6 +8,10 @@ test_description='git-read-tree --prefix test.
 
 . ./test-lib.sh
 
+cmp () {
+	diff -w "$@"
+}
+
 test_expect_success setup '
 	echo hello >one &&
 	git-update-index --add one &&
diff --git a/t/t4109-apply-multifrag.sh b/t/t4109-apply-multifrag.sh
index 5988e1ae4c..20f46fc1ca 100755
--- a/t/t4109-apply-multifrag.sh
+++ b/t/t4109-apply-multifrag.sh
@@ -9,6 +9,10 @@ test_description='git-apply test patches with multiple fragments.
 '
 . ./test-lib.sh
 
+cmp () {
+	diff -w "$@"
+}
+
 # setup
 
 cat > patch1.patch <<\EOF
diff --git a/t/t4110-apply-scan.sh b/t/t4110-apply-scan.sh
index 005f744816..c7cbe4ef64 100755
--- a/t/t4110-apply-scan.sh
+++ b/t/t4110-apply-scan.sh
@@ -9,6 +9,10 @@ test_description='git-apply test for patches which require scanning forwards and
 '
 . ./test-lib.sh
 
+cmp () {
+	diff -w "$@"
+}
+
 # setup
 
 cat > patch1.patch <<\EOF