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Quick Test CLI is a cross-platform tool designed for fast and easy stress testing in competitive programming. This guide will help you run your first stress test.

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What is stress testing?

Stress testing in competitive programming helps you:
  • Find edge cases where your solution fails
  • Verify correctness against a brute-force solution
  • Detect time limit exceeded (TLE) issues
  • Test with hundreds or thousands of random inputs automatically

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Prerequisites

Before you begin, ensure you have:
  • Quick Test CLI installed (see installation guide)
  • A compiler for your programming language (g++, python3, javac, etc.)
  • Basic familiarity with competitive programming

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Your first stress test

1

Prepare your files

You’ll need three files for a basic stress test with quicktest cmp:
  • Target file: Your optimized solution to test
  • Correct file: A brute-force solution (slower but guaranteed correct)
  • Generator file: Creates random test cases
Create a directory for your problem:
mkdir my-problem
cd my-problem
2

Write a generator

Create gen.cpp to generate random test cases:
gen.cpp
#include <bits/stdc++.h>
using namespace std;

int main(int argc, char* argv[]) {
    // quicktest passes a seed as an argument
    int seed = stoi(string(argv[1]));
    srand(seed);

    int n = rand() % 1000 + 1;
    cout << n << "\n";

    default_random_engine generator;
    uniform_int_distribution<int> distribution(-100000, 100000);

    for(int i = 0; i < n; i++) {
        if(i > 0) cout << " ";
        cout << distribution(generator);
    }
    return 0;
}
The generator must accept a seed argument from quicktest to ensure reproducible test cases.
3

Write the correct solution

Create correct.cpp with a brute-force approach:
correct.cpp
#include <bits/stdc++.h>
using namespace std;

int main() {
    // Maximum Subarray Problem - O(n²) solution
    int n; cin >> n;
    vector<int> values(n);
    for(int &a: values)
        cin >> a;
    
    int best = 0;
    for (int i = 0; i < n; i++) {
        int sum = 0;
        for (int j = i; j < n; j++) {
            sum += values[j];
            best = max(best, sum);
        }
    }
    cout << best << "\n";
    return 0;
}
4

Write your target solution

Create main.cpp with your optimized solution:
main.cpp
#include <bits/stdc++.h>
using namespace std;

int main() {
    // Maximum Subarray Problem - O(n) solution
    int n; cin >> n;
    vector<int> values(n);
    for(int &a: values)
        cin >> a;
    
    int best = 0, sum = 0;
    for (int i = 0; i < n; i++) {
        sum = max(values[i], sum + values[i]);
        best = max(best, sum);
    }
    cout << best << "\n";
    return 0;
}
5

Run the stress test

Execute the comparison test:
quicktest cmp --target-file=main.cpp --correct-file=correct.cpp --gen-file=gen.cpp --test-cases=100 --timeout=1000
Or use the shorter alias:
qt cmp -t main.cpp -c correct.cpp -g gen.cpp --tc 100 --tout 1000
Use qt as a shorthand for quicktest to save time during contests.
6

Interpret the results

Quick Test will show you:
  • AC (Accepted): Output matches the correct solution
  • WA (Wrong Answer): Output differs from the correct solution
  • TLE (Time Limit Exceeded): Execution exceeded the timeout
  • RTE (Runtime Error): Program crashed or exited with an error
If you find a WA, use --save-bad to save failing test cases:
qt cmp -t main.cpp -c correct.cpp -g gen.cpp --tc 100 --tout 1000 --save-bad
Test cases are saved in the .qt/testcases/ directory.

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Understanding test modes

Quick Test provides different testing modes for various scenarios:
Use when you have a brute-force solution to verify correctness.
qt cmp -t main.cpp -c correct.cpp -g gen.cpp --tc 500
Best for: Finding wrong answer bugs
Use when you only want to check for TLE issues without comparing outputs.
qt stress -t main.cpp -g gen.cpp --tc 100 --tout 1000
Best for: Performance testing
Use for problems with multiple valid answers (requires a checker script).
qt check -t main.cpp -c checker.cpp -g gen.cpp --tc 500
Best for: Problems with multiple correct outputs
Use to run your solution against pre-made test cases.
qt output -t main.cpp -p test_cases/testcase_ac
Best for: Testing with official sample inputs

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Quick reference

CommandPurposeRequired Files
qt cmpCompare outputstarget, correct, generator
qt stressCheck time limitstarget, generator
qt checkCustom validationtarget, checker, generator
qt outputRun saved teststarget, test files

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Next steps

Configuration

Customize compiler flags and language settings

Examples

Explore real-world usage patterns

Troubleshooting

Fix common issues

CLI Reference

View all available commands and options

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