default void copyFileToContainer(MountableFile mountableFile, String containerPath) {
        File sourceFile = new File(mountableFile.getResolvedPath());

        if (containerPath.endsWith("/") && sourceFile.isFile()) {
            final Logger logger = LoggerFactory.getLogger(GenericContainer.class);
            logger.warn(
                "folder-like containerPath in copyFileToContainer is deprecated, please explicitly specify a file path"
            );
            copyFileToContainer((Transferable) mountableFile, containerPath + sourceFile.getName());
        } else {
            copyFileToContainer((Transferable) mountableFile, containerPath);
        }
    }
Copies a file or directory to the container.

@param mountableFile file or directory which is copied into the container
@param containerPath destination path inside the container
core/src/main/java/org/testcontainers/containers/ContainerState.java