Android Patterns.WEB_URL坏了？

问：

那么，有人可以解释一下在我的测试中尾部斜杠发生了什么吗？还是WEB_URL模式的错误？

@Test
public void testWebUrl() {
    String url = "http://www.google.com/foo/";
    String test = "A string that fails is this: " + url + " <-- see that?";

    Matcher m = Patterns.WEB_URL.matcher(test);
    while (m.find()) {
        assertTrue(Patterns.WEB_URL.matcher(url).matches());  // PASSES
        assertEquals(m.group(), url);  // FAILS
        // Here, m.group() == "http://www.google.com/foo", without the trailing "/"
    }
}