Method available

tests/fl/stl/istream.cpp:241–243

    InputMocker(const char* input_data) : mData(input_data), mPos(0) {}

    int available() {
        return (mPos < mData.size()) ? (mData.size() - mPos) : 0;
    }

    int read() {
        if (mPos < mData.size()) {