diff --git a/src/test/CMakeLists.txt b/src/test/CMakeLists.txt
index 206dc0530..2298653bf 100644
--- a/src/test/CMakeLists.txt
+++ b/src/test/CMakeLists.txt
@@ -54,6 +54,7 @@ add_executable(test-z3
   expr_substitution.cpp
   ext_numeral.cpp
   f2n.cpp
+  finite_sets.cpp
   factor_rewriter.cpp
   finder.cpp
   fixed_bit_vector.cpp
diff --git a/src/test/finite_sets.cpp b/src/test/finite_sets.cpp
new file mode 100644
index 000000000..934541213
--- /dev/null
+++ b/src/test/finite_sets.cpp
@@ -0,0 +1,120 @@
+/*++
+Copyright (c) 2025 Microsoft Corporation
+
+Module Name:
+
+    tst_finite_sets.cpp
+
+Abstract:
+
+    Test finite sets decl plugin
+
+Author:
+
+    GitHub Copilot Agent 2025
+
+Revision History:
+
+--*/
+#include "ast/ast.h"
+#include "ast/finite_sets_decl_plugin.h"
+#include "ast/reg_decl_plugins.h"
+#include "ast/arith_decl_plugin.h"
+
+static void tst_finite_sets_basic() {
+    ast_manager m;
+    reg_decl_plugins(m);
+    
+    finite_sets_util fsets(m);
+    arith_util arith(m);
+    
+    // Test creating a finite set sort
+    sort_ref int_sort(arith.mk_int(), m);
+    parameter param(int_sort.get());
+    sort_ref finite_set_int(m.mk_sort(fsets.get_family_id(), FINITE_SET_SORT, 1, &param), m);
+    
+    ENSURE(fsets.is_finite_set(finite_set_int.get()));
+    
+    // Test creating empty set
+    app_ref empty_set(fsets.mk_empty(int_sort), m);
+    ENSURE(fsets.is_empty(empty_set.get()));
+    ENSURE(empty_set->get_sort() == finite_set_int.get());
+    
+    // Test set.range
+    expr_ref zero(arith.mk_int(0), m);
+    expr_ref ten(arith.mk_int(10), m);
+    app_ref range_set(fsets.mk_range(zero, ten), m);
+    ENSURE(fsets.is_range(range_set.get()));
+    ENSURE(range_set->get_sort() == finite_set_int.get());
+    
+    // Test set.union
+    app_ref union_set(fsets.mk_union(empty_set, range_set), m);
+    ENSURE(fsets.is_union(union_set.get()));
+    ENSURE(union_set->get_sort() == finite_set_int.get());
+    
+    // Test set.intersect
+    app_ref intersect_set(fsets.mk_intersect(range_set, range_set), m);
+    ENSURE(fsets.is_intersect(intersect_set.get()));
+    ENSURE(intersect_set->get_sort() == finite_set_int.get());
+    
+    // Test set.difference
+    app_ref diff_set(fsets.mk_difference(range_set, empty_set), m);
+    ENSURE(fsets.is_difference(diff_set.get()));
+    ENSURE(diff_set->get_sort() == finite_set_int.get());
+    
+    // Test set.in
+    expr_ref five(arith.mk_int(5), m);
+    app_ref in_expr(fsets.mk_in(five, range_set), m);
+    ENSURE(fsets.is_in(in_expr.get()));
+    ENSURE(m.is_bool(in_expr->get_sort()));
+    
+    // Test set.size
+    app_ref size_expr(fsets.mk_size(range_set), m);
+    ENSURE(fsets.is_size(size_expr.get()));
+    ENSURE(arith.is_int(size_expr->get_sort()));
+    
+    // Test set.subset
+    app_ref subset_expr(fsets.mk_subset(empty_set, range_set), m);
+    ENSURE(fsets.is_subset(subset_expr.get()));
+    ENSURE(m.is_bool(subset_expr->get_sort()));
+}
+
+static void tst_finite_sets_map_filter() {
+    ast_manager m;
+    reg_decl_plugins(m);
+    
+    finite_sets_util fsets(m);
+    arith_util arith(m);
+    
+    // Create Int and Bool sorts
+    sort_ref int_sort(arith.mk_int(), m);
+    sort_ref bool_sort(m.mk_bool_sort(), m);
+    
+    // Create finite set sorts
+    parameter int_param(int_sort.get());
+    sort_ref finite_set_int(m.mk_sort(fsets.get_family_id(), FINITE_SET_SORT, 1, &int_param), m);
+    
+    // Create a function Int -> Int for map
+    func_decl_ref inc_func(m.mk_func_decl(symbol("inc"), int_sort.get(), int_sort.get()), m);
+    
+    // Create a set and test map
+    expr_ref zero(arith.mk_int(0), m);
+    expr_ref ten(arith.mk_int(10), m);
+    app_ref range_set(fsets.mk_range(zero, ten), m);
+    
+    app_ref mapped_set(fsets.mk_map(inc_func, range_set), m);
+    ENSURE(fsets.is_map(mapped_set.get()));
+    ENSURE(mapped_set->get_sort() == finite_set_int.get());
+    
+    // Create a function Int -> Bool for filter
+    func_decl_ref is_even(m.mk_func_decl(symbol("is_even"), int_sort.get(), bool_sort.get()), m);
+    
+    app_ref filtered_set(fsets.mk_filter(is_even, range_set), m);
+    ENSURE(fsets.is_filter(filtered_set.get()));
+    ENSURE(filtered_set->get_sort() == finite_set_int.get());
+}
+
+void tst_finite_sets() {
+    tst_finite_sets_basic();
+    tst_finite_sets_map_filter();
+}
diff --git a/src/test/main.cpp b/src/test/main.cpp
index c6bb23378..feddbd9fd 100644
--- a/src/test/main.cpp
+++ b/src/test/main.cpp
@@ -282,4 +282,5 @@ int main(int argc, char ** argv) {
     TST(scoped_vector);
     TST(sls_seq_plugin);
     TST(ho_matcher);
+    TST(finite_sets);
 }