C++ mock test for competitive programming

main.cpp

#include <bits/stdc++.h>

using namespace std;

void run(istream &in, ostream &out) {
    // write your code here
    int x;
    while (in >> x) {
        out << x * 2 << '\n';
    }
}

void trimR(string &s) { s.erase(find_if(s.rbegin(), s.rend(), [](int ch) { return !isspace(ch); }).base(), s.end()); }

int main() {
// for CLion, add one line `add_definitions(-DMOCK)` in CMakeLists.txt
#ifdef MOCK
    vector<vector<string>> examples = {
            // add example inputs and outputs, or your custom test data
            {
                    R"(2 3)", // input
                    R"(4
6)", // output
            },
            {
                    R"(-5 -6)", // input
                    R"(-10
-12)", // output
            },
    };
    bool passedAll = true;
    for (int i = 0; i < examples.size(); i++) {
        string rawIn = examples[i][0], expectedOut = examples[i][1];
        trimR(expectedOut);
        istringstream mockIn(rawIn);
        ostringstream mockOut;
        run(mockIn, mockOut);
        string actualOut = mockOut.str();
        trimR(actualOut);
        if (expectedOut != actualOut) {
            passedAll = false;
            cout << "WA " << i + 1 << endl;
            cout << "Input:" << endl << rawIn << endl;
            cout << "Expected:" << endl << expectedOut << endl;
            cout << "Actual:" << endl << actualOut << endl << endl;
        }
    }
    if (passedAll) {
        cout << "OK! SUBMIT" << endl;
    }
#else
    ios::sync_with_stdio(false), cin.tie(nullptr);
    run(cin, cout);
#endif
    return 0;
}