LayoutTests/fetch/body-init.html

<!DOCTYPE html>
<script src='../resources/testharness.js'></script>
<script src='../resources/testharnessreport.js'></script>
<script>

promise_test(() => {
    return new Response(1).text().then((text) => {
        assert_equals(text, "1");
    });
}, "Testing integer body passed to response");

promise_test(() => {
    return new Response({}).text().then((text) => {
        assert_equals(text, "[object Object]");
    });
}, "Testing object body passed to response");

promise_test(() => {
    return new Request("", {method: "POST", body: 1}).text().then((text) => {
        assert_equals(text, "1");
    });
}, "Testing integer body passed to request");

promise_test(() => {
    return new Request("", {method: "POST", body: {}}).text().then((text) => {
        assert_equals(text, "[object Object]");
    });
}, "Testing object body passed to request");

</script>