java-tutorials/libraries/src/test/java/com/baeldung/streamutils/CopyStreamUnitTest.java

package com.baeldung.streamutils;

import static org.junit.Assert.assertTrue;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;

import org.junit.Assert;
import org.junit.Test;
import org.springframework.util.StreamUtils;

import static com.baeldung.streamutils.CopyStream.getStringFromInputStream;

public class CopyStreamUnitTest {

    @Test
    public void whenCopyInputStreamToOutputStream_thenCorrect() throws IOException {
        String inputFileName = "src/test/resources/input.txt";
        String outputFileName = "src/test/resources/output.txt";
        File outputFile = new File(outputFileName);
        InputStream in = new FileInputStream(inputFileName);
        OutputStream out = new FileOutputStream(outputFileName);

        StreamUtils.copy(in, out);

        assertTrue(outputFile.exists());
        String inputFileContent = getStringFromInputStream(new FileInputStream(inputFileName));
        String outputFileContent = getStringFromInputStream(new FileInputStream(outputFileName));
        Assert.assertEquals(inputFileContent, outputFileContent);
    }

    @Test
    public void whenCopyRangeOfInputStreamToOutputStream_thenCorrect() throws IOException {
        String inputFileName = "src/test/resources/input.txt";
        String outputFileName = "src/test/resources/output.txt";
        File outputFile = new File(outputFileName);
        InputStream in = new FileInputStream(inputFileName);
        OutputStream out = new FileOutputStream(outputFileName);

        StreamUtils.copyRange(in, out, 1, 10);

        assertTrue(outputFile.exists());
        String inputFileContent = getStringFromInputStream(new FileInputStream(inputFileName));
        String outputFileContent = getStringFromInputStream(new FileInputStream(outputFileName));
        Assert.assertEquals(inputFileContent.substring(1, 11), outputFileContent);
    }

    @Test
    public void whenCopyStringToOutputStream_thenCorrect() throws IOException {
        String string = "Should be copied to OutputStream.";
        String outputFileName = "src/test/resources/output.txt";
        File outputFile = new File(outputFileName);
        OutputStream out = new FileOutputStream("src/test/resources/output.txt");

        StreamUtils.copy(string, StandardCharsets.UTF_8, out);

        assertTrue(outputFile.exists());
        String outputFileContent = getStringFromInputStream(new FileInputStream(outputFileName));
        Assert.assertEquals(outputFileContent, string);
    }

    @Test
    public void whenCopyInputStreamToString_thenCorrect() throws IOException {
        String inputFileName = "src/test/resources/input.txt";
        InputStream is = new FileInputStream(inputFileName);
        String content = StreamUtils.copyToString(is, StandardCharsets.UTF_8);

        String inputFileContent = getStringFromInputStream(new FileInputStream(inputFileName));
        Assert.assertEquals(inputFileContent, content);
    }

    @Test
    public void whenCopyByteArrayToOutputStream_thenCorrect() throws IOException {
        String outputFileName = "src/test/resources/output.txt";
        String string = "Should be copied to OutputStream.";
        byte[] byteArray = string.getBytes();
        OutputStream out = new FileOutputStream("src/test/resources/output.txt");

        StreamUtils.copy(byteArray, out);
        String outputFileContent = getStringFromInputStream(new FileInputStream(outputFileName));
        Assert.assertEquals(outputFileContent, string);
    }

    @Test
    public void whenCopyInputStreamToByteArray_thenCorrect() throws IOException {
        String inputFileName = "src/test/resources/input.txt";
        InputStream in = new FileInputStream(inputFileName);
        byte[] out = StreamUtils.copyToByteArray(in);

        String content = new String(out);
        String inputFileContent = getStringFromInputStream(new FileInputStream(inputFileName));
        Assert.assertEquals(inputFileContent, content);
    }

}