How to assertThat something is null with Hamcrest?

问题

How would I assertThat something is null?

for example

 assertThat(attr.getValue(), is(""));

But I get an error saying that I cannot have null in is(null).

回答1:

You can use IsNull.nullValue() method:

import static org.hamcrest.Matchers.is;
import static org.hamcrest.Matchers.nullValue;

assertThat(attr.getValue(), is(nullValue()));

回答2:

why not use assertNull(object) / assertNotNull(object) ?

回答3:

If you want to hamcrest, you can do

import static org.hamcrest.Matchers.nullValue;

assertThat(attr.getValue(), is(nullValue()));

In Junit you can do

import static junit.framework.Assert.assertNull;
assertNull(object);

回答4:

Use the following (from Hamcrest):

assertThat(attr.getValue(), is(nullValue()));

来源：https://stackoverflow.com/questions/18987692/how-to-assertthat-something-is-null-with-hamcrest