diff --git a/test/buffers_utest.cpp b/test/buffers_utest.cpp
index db22e312..8002eee3 100644
--- a/test/buffers_utest.cpp
+++ b/test/buffers_utest.cpp
@@ -34,6 +34,7 @@
 #include "quadiron.h"
 
 namespace vec = quadiron::vec;
+namespace gf = quadiron::gf;
 
 template <typename T>
 class BuffersTest : public ::testing::Test {
@@ -58,6 +59,73 @@ class BuffersTest : public ::testing::Test {
 
         return vec;
     }
+
+    std::unique_ptr<vec::Vector<T>>
+    gen_rand_vector(gf::RingModN<T>& gf, size_t n, T max_val)
+    {
+        std::vector<T> mem;
+        mem.reserve(max_val);
+
+        for (size_t i = 0; i < max_val; i++) {
+            mem.push_back(i);
+        }
+        std::random_shuffle(mem.begin(), mem.end());
+
+        auto vec = std::unique_ptr<vec::Vector<T>>(new vec::Vector<T>(gf, n));
+        for (size_t i = 0; i < n; i++) {
+            vec->set(i, mem[i]);
+        }
+        return vec;
+    }
+
+    bool check_eq(const T* buf1, const T* buf2, size_t len)
+    {
+        return memcmp(buf1, buf2, len * sizeof(T)) == 0;
+    }
+
+    bool check_all_zeros(const T* buf, size_t len)
+    {
+        for (size_t i = 0; i < len; ++i) {
+            if (buf[i] != 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    bool check_shuffled_bufs(
+        const vec::Buffers<T>& input,
+        const vec::Buffers<T>& output,
+        const vec::Vector<T>& map)
+    {
+        const size_t input_len = input.get_n();
+        const size_t output_len = output.get_n();
+        const size_t map_len = map.get_n();
+
+        const size_t size = input.get_size();
+
+        std::vector<bool> check(output.get_n(), false);
+
+        for (unsigned i = 0; i < map_len; ++i) {
+            if (!check_eq(input.get(i), output.get(map.get(i)), size)) {
+                return false;
+            }
+            check[map.get(i)] = true;
+        }
+
+        // Check zero-extended if it's necessary
+        if (output_len > input_len) {
+            for (size_t i = 0; i < output_len; ++i) {
+                if (!check[i]) {
+                    if (!check_all_zeros(output.get(i), size)) {
+                        return false;
+                    }
+                }
+            }
+        }
+
+        return true;
+    }
 };
 
 using TestedTypes = ::testing::Types<uint32_t, uint64_t>;
@@ -68,7 +136,7 @@ TYPED_TEST(BuffersTest, TestConstructors) // NOLINT
     const int n = 16;
     const int begin = 5;
     const int end = 12;
-    const int size = 32;
+    const int size = 4;
 
     auto vec1 = this->gen_buffers_rand_data(n, size);
     vec::Buffers<TypeParam> vec2(*vec1, begin, end);
@@ -92,6 +160,20 @@ TYPED_TEST(BuffersTest, TestConstructors) // NOLINT
     vec::Buffers<TypeParam> vec3(end - begin, size, mem3);
 
     ASSERT_EQ(vec2, vec3);
+
+    auto gf(gf::create<gf::Prime<TypeParam>>(65537));
+
+    // no-extension
+    const int out_n_1 = n - 5;
+    auto map_1 = this->gen_rand_vector(gf, out_n_1, out_n_1);
+    vec::Buffers<TypeParam> vec4(*vec1, *map_1, out_n_1);
+    ASSERT_TRUE(this->check_shuffled_bufs(*vec1, vec4, *map_1));
+
+    // extension
+    const int out_n_2 = n + 10;
+    auto map_2 = this->gen_rand_vector(gf, n, out_n_2);
+    vec::Buffers<TypeParam> vec5(*vec1, *map_2, out_n_2);
+    ASSERT_TRUE(this->check_shuffled_bufs(*vec1, vec5, *map_2));
 }
 
 TYPED_TEST(BuffersTest, TestEvenOddSeparation) // NOLINT