Cover LoadBalancer with tests (#1394)

Fixes #680. Fixes #1222.

tests/unit/util/RandomTests.cpp

@@ -0,0 +1,62 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2024, the clio developers.
+
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include "util/Random.hpp"
+
+#include <gtest/gtest.h>
+
+#include <algorithm>
+#include <cstddef>
+#include <iterator>
+#include <vector>
+
+using namespace util;
+
+struct RandomTests : public ::testing::Test {
+    static std::vector<int>
+    generateRandoms(size_t const numRandoms = 1000)
+    {
+        std::vector<int> v;
+        v.reserve(numRandoms);
+        std::ranges::generate_n(std::back_inserter(v), numRandoms, []() { return Random::uniform(0, 1000); });
+        return v;
+    }
+};
+
+TEST_F(RandomTests, Uniform)
+{
+    std::ranges::for_each(generateRandoms(), [](int const& e) {
+        EXPECT_GE(e, 0);
+        EXPECT_LE(e, 1000);
+    });
+}
+
+TEST_F(RandomTests, FixedSeed)
+{
+    Random::setSeed(42);
+    std::vector<int> const v1 = generateRandoms();
+
+    Random::setSeed(42);
+    std::vector<int> const v2 = generateRandoms();
+
+    ASSERT_EQ(v1.size(), v2.size());
+    for (size_t i = 0; i < v1.size(); ++i) {
+        EXPECT_EQ(v1[i], v2[i]);
+    };
+}