diff --git a/include/aare/InclusiveROI.hpp b/include/aare/InclusiveROI.hpp
index 7936ac5f..6e385bf6 100644
--- a/include/aare/InclusiveROI.hpp
+++ b/include/aare/InclusiveROI.hpp
@@ -34,6 +34,11 @@ struct InclusiveROI {
         return xmin >= 0 && ymin >= 0 && xmax < ncols && ymax < nrows;
     }
 
+    constexpr bool operator==(InclusiveROI const &other) const noexcept {
+        return xmin == other.xmin && xmax == other.xmax && ymin == other.ymin &&
+               ymax == other.ymax;
+    }
+
     static InclusiveROI emptyROI() noexcept { return {0, -1, 0, -1}; }
     // TODO (nice to have)
     // static InclusiveROI from_shape(ssize_t width, ssize_t height);
diff --git a/src/InclusiveROI.test.cpp b/src/InclusiveROI.test.cpp
new file mode 100644
index 00000000..77029986
--- /dev/null
+++ b/src/InclusiveROI.test.cpp
@@ -0,0 +1,16 @@
+#include "aare/InclusiveROI.hpp"
+#include <catch2/catch_test_macros.hpp>
+
+using namespace aare;
+
+TEST_CASE("mirror_on_y mirrors ROI about vertical axis",
+          "[InlusiveROIgeometry]") {
+
+    SECTION("ROI on left side of axis") {
+        InclusiveROI roi{1, 3, 10, 20};
+
+        auto mirrored = inclusiveroi::geom::mirror_on_y(roi, 5);
+
+        REQUIRE(mirrored == InclusiveROI{6, 8, 10, 20});
+    }
+}
\ No newline at end of file