quickCheck

// https://rosettacode.org/wiki/Sorting_algorithms/Bubble_sort#D
static T[] bubbleSort(T)(T[] data) pure nothrow
{
    import std.algorithm : swap;
    foreach_reverse (n; 0 .. data.length)
    {
        bool swapped;
        foreach (i; 0 .. n)
            if (data[i] > data[i + 1]) {
                swap(data[i], data[i + 1]);
                swapped = true;
            }
        if (!swapped)
            break;
    }
    return data;
}

/// random data is injected into testee arguments
static bool testee(ubyte[] data)
{
    import std.algorithm : equal, sort;

    return bubbleSort(data.dup).equal(data.sort());
}

quickCheck!testee;

static QCheckResult testee(string haystack, string needle)
{
    import std.algorithm : canFind, boyerMooreFinder;

    if (needle.length < haystack.length)
        return QCheckResult.discard;

    auto bmFinder = boyerMooreFinder(needle);
    immutable found = !!bmFinder.beFound(haystack).length;
    return found == haystack.canFind(needle) ? QCheckResult.pass : QCheckResult.fail;
}

randomSeed = 42;
quickCheck!testee;