diff --git a/src/tests/library/CMakeLists.txt b/src/tests/library/CMakeLists.txt
index 5295d8c5b..2e77de8b4 100644
--- a/src/tests/library/CMakeLists.txt
+++ b/src/tests/library/CMakeLists.txt
@@ -7,3 +7,6 @@ add_test(ho_unifier ${CMAKE_CURRENT_BINARY_DIR}/ho_unifier)
 add_executable(formatter formatter.cpp)
 target_link_libraries(formatter ${EXTRA_LIBS})
 add_test(formatter ${CMAKE_CURRENT_BINARY_DIR}/formatter)
+add_executable(max_sharing max_sharing.cpp)
+target_link_libraries(max_sharing ${EXTRA_LIBS})
+add_test(max_sharing ${CMAKE_CURRENT_BINARY_DIR}/max_sharing)
diff --git a/src/tests/library/max_sharing.cpp b/src/tests/library/max_sharing.cpp
new file mode 100644
index 000000000..c0df46234
--- /dev/null
+++ b/src/tests/library/max_sharing.cpp
@@ -0,0 +1,50 @@
+/*
+Copyright (c) 2013 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#include <iostream>
+#include "util/test.h"
+#include "kernel/abstract.h"
+#include "library/max_sharing.h"
+#include "library/printer.h"
+using namespace lean;
+
+static void tst1() {
+    max_sharing_fn max_fn;
+    expr a1 = Const("a");
+    expr a2 = Const("a");
+    expr F1 = Eq(a1, a2);
+    lean_assert(!is_eqp(eq_lhs(F1), eq_rhs(F1)));
+    expr F2 = max_fn(F1);
+    lean_assert(is_eqp(eq_lhs(F2), eq_rhs(F2)));
+    expr x = Const("x");
+    expr y = Const("y");
+    expr f = Const("f");
+    expr N = Const("N");
+    F1 = f(Fun({x, N}, f(x, x)), Fun({y, N}, f(y, y)));
+    lean_assert(!is_eqp(arg(F1, 1), arg(F1, 2)));
+    F2 = max_fn(F1);
+    std::cout << F2 << "\n";
+    lean_assert(is_eqp(arg(F2, 1), arg(F2, 2)));
+    max_fn.clear();
+    meta_ctx ctx{mk_lift(1, 1), mk_inst(0, a1)};
+    expr m1 = mk_metavar(0, ctx);
+    expr m2 = mk_metavar(0, ctx);
+    F1 = f(m1, m2);
+    lean_assert(!is_eqp(arg(F1, 1), arg(F1, 2)));
+    F2 = max_fn(F1);
+    std::cout << F2 << "\n";
+    lean_assert(is_eqp(arg(F2, 1), arg(F2, 2)));
+    F1 = f(Let({x, f(a1)}, f(x, x)), Let({y, f(a1)}, f(y, y)));
+    lean_assert(!is_eqp(arg(F1, 1), arg(F1, 2)));
+    F2 = max_fn(F1);
+    std::cout << F2 << "\n";
+    lean_assert(is_eqp(arg(F2, 1), arg(F2, 2)));
+}
+
+int main() {
+    tst1();
+    return has_violations() ? 1 : 0;
+}