StyleSheets = [whiteStyleSheet];
    assert_equals(getComputedStyle(greenSpan).color, "rgb(0, 0, 0)");
    assert_equals(getComputedStyle(redSpan).color, "rgb(0, 0, 0)");
    assert_equals(getComputedStyle(blueSpan).color, "rgb(0, 0, 0)");
    assert_equals(getComputedStyle(whiteSpan).color, "rgb(0, 0, 0)");
    assert_equals(getComputedStyle(yellowSpan).color, "rgb(0, 0, 0)");

    // disable dsheets don't block other styles from applying
    document.adoptedStyleSheets = [greenStyleSheet, blueStyleSheet];