verify(tree, times(1)).release(); // closed on constructor failure
    }

    @Test
    @DisplayName("Iteration skips '.' and '..' and returns valid entries")
    void iterationSkipsDotAndDotDot() throws Exception {
        // Arrange
        stubAcquireReturnsSelf();
        FileEntry initial = entry("a");
        // Include entries that should be skipped by internal filter