问断言InputStream和输出流相等

EN

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.springframework.util.StreamUtils;

public class Stack {

    public static void copy(InputStream in, OutputStream out) {
        try {
            StreamUtils.copy(in, out);
        } catch(IOException io) {
            throw new RuntimeException("BOOM!");
        }
    }
}

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.Arrays;

import org.junit.Test;

public class StackTest {

    @Test
    public void shouldCopyFromInputToOutput() {
        byte[] contents = new byte[] { 1, 2, 3 };

        ByteArrayOutputStream out = new ByteArrayOutputStream();

        Stack.copy(new ByteArrayInputStream(contents), out);

        byte[] written = out.toByteArray();

        assert Arrays.equals(contents, written);
    }
}