private static void assertFilesCopied() {
    // the Dockerfile should have been copied, or generated if no docker directory was specified
    assertFileExists("target/docker/Dockerfile");

    // files from resources/copy1
    // files including a file with dollar sign because it has to be escaped inside the dockerfile
    assertFileExists("target/docker/resources/parent/escapedollar$sign.xml");
    assertFileExists("target/docker/resources/parent/parent.xml");
    assertFileExists("target/docker/resources/parent/child/child.xml");
    assertFileDoesNotExist("target/docker/resources/parent/parent.json");
    assertFileDoesNotExist("target/docker/resources/parent/child/child-exclude.xml");

    // file from resources/copy2
    assertFileExists("target/docker/copy2.json");
  }
Test what happens if tagInfoFile does not contain a path, i.e. the value is simply
"image_info.json".
src/test/java/com/spotify/docker/BuildMojoTest.java