java-topology/defects/calligra-0001/test/CalligraShapeManagerAddTest.java

import java.util.*;

/**
 * Unit test for calligra-0001: KoShapeManager addShape O(N^2) membership check.
 *
 * Defect: libs/flake/KoShapeManager.cpp addShape()
 *   if (d->shapes.contains(shape))  // QList::contains is O(N)
 *   d->shapes.append(shape);
 *
 * Called from setShapes() in a loop over N shapes, producing O(N^2) total.
 *
 * Fix: change d->shapes from QList to QSet, making contains() O(1).
 *
 * Complexity: O(N^2) -> O(N).
 */
public class CalligraShapeManagerAddTest {

    // --- Defective implementation: QList equivalent ---
    static List<Integer> buildShapeListLinear(int[] shapes) {
        List<Integer> result = new ArrayList<>();
        for (int shape : shapes) {
            if (!result.contains(shape)) { // O(N) each
                result.add(shape);
            }
        }
        return result;
    }

    // --- Fixed implementation: QSet equivalent ---
    static Set<Integer> buildShapeSetFixed(int[] shapes) {
        Set<Integer> result = new LinkedHashSet<>();
        for (int shape : shapes) {
            result.add(shape); // O(1) each, set deduplicates automatically
        }
        return result;
    }

    // --- Benchmark ---
    static long benchmarkLinear(int N) {
        int[] shapes = new int[N];
        for (int i = 0; i < N; i++) shapes[i] = i; // all unique -> worst case
        long start = System.nanoTime();
        buildShapeListLinear(shapes);
        return System.nanoTime() - start;
    }

    static long benchmarkFixed(int N) {
        int[] shapes = new int[N];
        for (int i = 0; i < N; i++) shapes[i] = i;
        long start = System.nanoTime();
        buildShapeSetFixed(shapes);
        return System.nanoTime() - start;
    }

    public static void main(String[] args) {
        System.out.println("=== calligra-0001: KoShapeManager addShape dedup O(N^2) ===");

        // Correctness: unique shapes
        {
            int[] shapes = {10, 20, 30, 40, 50};
            List<Integer> linear = buildShapeListLinear(shapes);
            Set<Integer> fixed = buildShapeSetFixed(shapes);
            if (!new HashSet<>(linear).equals(fixed)) {
                System.err.println("FAIL: unique-shape mismatch linear=" + linear + " fixed=" + fixed);
                System.exit(1);
            }
            System.out.println("PASS: unique shapes, result size=" + fixed.size());
        }

        // Correctness: duplicate shapes (setShapes called with duplicates)
        {
            int[] shapes = {1, 2, 3, 2, 1, 4};
            List<Integer> linear = buildShapeListLinear(shapes);
            Set<Integer> fixed = buildShapeSetFixed(shapes);
            if (!new HashSet<>(linear).equals(fixed)) {
                System.err.println("FAIL: duplicate-shape mismatch linear=" + linear + " fixed=" + fixed);
                System.exit(1);
            }
            if (linear.size() != 4 || fixed.size() != 4) {
                System.err.println("FAIL: expected 4 unique shapes, linear=" + linear.size() + " fixed=" + fixed.size());
                System.exit(1);
            }
            System.out.println("PASS: duplicate shapes deduped correctly, result size=" + fixed.size());
        }

        // Performance test
        int N = 5000;
        // Warmup
        for (int w = 0; w < 3; w++) { benchmarkLinear(N/10); benchmarkFixed(N/10); }

        long linearNs = benchmarkLinear(N);
        long fixedNs = benchmarkFixed(N);
        double ratio = (double) linearNs / fixedNs;

        System.out.printf("Linear  N=%d: %,d ns%n", N, linearNs);
        System.out.printf("Fixed   N=%d: %,d ns%n", N, fixedNs);
        System.out.printf("Speedup: %.1fx%n", ratio);

        if (ratio < 5.0) {
            System.err.printf("FAIL: expected >= 5x speedup at N=%d, got %.1fx%n", N, ratio);
            System.exit(1);
        }
        System.out.println("PASS: speedup >= 5x");
        System.out.println("PASS: all tests passed");
    }
}