TestFileCollection collection = new TestFileCollection(file1, file2)

        expect:
        assertThat(collection.getAsPath(), equalTo(file1.path + File.pathSeparator + file2.path))
    }

    void canAddCollectionsTogether() {
        File file1 = new File("f1")
        File file2 = new File("f2")
        File file3 = new File("f3")
        TestFileCollection collection1 = new TestFileCollection(file1, file2)