function run_test() { let result = Cc["@mozilla.org/autocomplete/simple-result;1"].createInstance( Ci.nsIAutoCompleteSimpleResult ); result.appendMatch("a", ""); result.appendMatch("b", ""); result.removeMatchAt(0); Assert.equal(result.matchCount, 1); Assert.equal(result.getValueAt(0), "b"); result.appendMatch("c", ""); result.removeMatchAt(1); Assert.equal(result.matchCount, 1); Assert.equal(result.getValueAt(0), "b"); result.removeMatchAt(0); Assert.equal(result.matchCount, 0); }