Cover LoadBalancer with tests (#1394)

Fixes #680. Fixes #1222.

src/etl/ETLHelpers.cpp

@@ -0,0 +1,46 @@
+//------------------------------------------------------------------------------
+/*
+    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 "etl/ETLHelpers.hpp"
+
+#include "util/Assert.hpp"
+
+#include <ripple/basics/base_uint.h>
+
+#include <cstddef>
+#include <vector>
+
+namespace etl {
+std::vector<ripple::uint256>
+getMarkers(size_t numMarkers)
+{
+    ASSERT(numMarkers <= 256, "Number of markers must be <= 256. Got: {}", numMarkers);
+
+    unsigned char const incr = 256 / numMarkers;
+
+    std::vector<ripple::uint256> markers;
+    markers.reserve(numMarkers);
+    ripple::uint256 base{0};
+    for (size_t i = 0; i < numMarkers; ++i) {
+        markers.push_back(base);
+        base.data()[0] += incr;
+    }
+    return markers;
+}
+}  // namespace etl