@Override
	protected String toDSL() {
		String dsl = FixtureUtils.labelOrEmpty(label);
		dsl += String.format("file --dir=%s --pattern='%s' --mode=%s", dir, fileName, mode);
		return dsl;
	}
Renders the default DSL for this fixture.
spring-xd-test-fixtures/src/main/java/org/springframework/xd/test/fixtures/SimpleFileSource.java