addValue() return value: -1 Rule count after calling addRule() with no arguments: 1 Rule text: undefined { } Rule count after calling addRule with no index: 2 Second rule text: .test { font-size: 14px; } Rule count after calling addRule with index 0: 3 Rule text: .test { padding: 100px; } Exception thrown when given a negative index: IndexSizeError Exception thrown when index out of range: IndexSizeError