update test

tests/libslic3r/test_multiple_beds.cpp

@@ -0,0 +1,35 @@
+#include <catch2/catch.hpp>
+
+#include <libslic3r/MultipleBeds.hpp>
+#include <numeric>
+
+using namespace Slic3r;
+TEST_CASE("Conversion between grid coords and index", "[MultipleBeds]")
+{
+    std::vector<BedsGrid::Index> original_indices(10);
+    std::iota(original_indices.begin(), original_indices.end(), 0);
+
+    // Add indexes covering the whole int positive range.
+    const int n{100};
+    std::generate_n(std::back_inserter(original_indices), n, [i = 1]() mutable {
+        return std::numeric_limits<int>::max() / n * i++;
+    });
+
+    std::vector<BedsGrid::GridCoords> coords;
+    std::transform(
+        original_indices.begin(),
+        original_indices.end(),
+        std::back_inserter(coords),
+        BedsGrid::index2grid_coords
+    );
+
+    std::vector<BedsGrid::Index> indices;
+    std::transform(
+        coords.begin(),
+        coords.end(),
+        std::back_inserter(indices),
+        BedsGrid::grid_coords2index
+    );
+
+    CHECK(original_indices == indices);
+}