Syncing a file between host and container with Testcontainers

CopySyncExperiment.java

package org.testcontainers;

import com.github.dockerjava.api.command.InspectContainerResponse;
import lombok.NonNull;
import lombok.SneakyThrows;
import org.apache.commons.io.FileUtils;
import org.junit.Test;
import org.testcontainers.containers.GenericContainer;
import org.testcontainers.utility.MountableFile;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.stream.Collectors;

import static org.rnorth.visibleassertions.VisibleAssertions.assertEquals;

public class CopySyncExperiment {

    @Test
    public void testForSync() throws IOException, InterruptedException {

        try (GenericContainer syncContainer = new SyncingContainer("redis:5.0.3-alpine")
            .withExposedPorts(6379)
            .withCopyFileToContainer(MountableFile.forHostPath("foobar"), "/sync/foobar")) {

            syncContainer.start();
            syncContainer.execInContainer("sh", "-c", "echo foo >> /sync/foobar");
        }

        String fileContentAfterSync = Files.lines(new File("foobar").toPath()).collect(Collectors.joining());
        assertEquals("File was not synced", "somecontentfoo", fileContentAfterSync);
    }

    public static class SyncingContainer extends GenericContainer {

        String syncPath;
        MountableFile syncFile;

        public SyncingContainer(@NonNull String dockerImageName) {
            super(dockerImageName);
        }

        @Override
        public GenericContainer withCopyFileToContainer(MountableFile mountableFile, String containerPath) {
            syncPath = containerPath;
            syncFile = mountableFile;
            return super.withCopyFileToContainer(mountableFile, containerPath);
        }

        @Override
        @SneakyThrows
        protected void containerIsStopping(InspectContainerResponse containerInfo) {
            FileUtils.deleteQuietly(new File(syncFile.getResolvedPath()));
            copyFileFromContainer(syncPath, syncFile.getResolvedPath());
            super.containerIsStopping(containerInfo);
        }
    }

}