43.4.3 OutputCapture

OutputCapture是JUnit的一个Rule，用于捕获System.out和System.err输出。你可以将@Rule注解capture，然后在断言中调用toString()。如下所示：

import org.junit.Rule;
import org.junit.Test;
import org.springframework.boot.test.rule.OutputCapture;

import static org.hamcrest.Matchers.*;
import static org.junit.Assert.*;

public class MyTest {

    @Rule
    public OutputCapture capture = new OutputCapture();

    @Test
    public void testName() throws Exception {
        System.out.println("Hello World!");
        assertThat(capture.toString(), containsString("World"));
    }

}