diff --git a/include/aare/NDView.hpp b/include/aare/NDView.hpp
index e7ad002..28f5371 100644
--- a/include/aare/NDView.hpp
+++ b/include/aare/NDView.hpp
@@ -67,20 +67,13 @@ class NDView : public ArrayExpr<NDView<T, Ndim>, Ndim> {
           size_(std::accumulate(std::begin(shape), std::end(shape), 1,
                                 std::multiplies<>())) {}
 
-    // NDView(T *buffer, const std::vector<ssize_t> &shape)
-    //     : buffer_(buffer),
-    //     strides_(c_strides<Ndim>(make_array<Ndim>(shape))),
-    //     shape_(make_array<Ndim>(shape)),
-    //       size_(std::accumulate(std::begin(shape), std::end(shape), 1,
-    //       std::multiplies<>())) {}
-
     template <typename... Ix>
     std::enable_if_t<sizeof...(Ix) == Ndim, T &> operator()(Ix... index) {
         return buffer_[element_offset(strides_, index...)];
     }
 
     template <typename... Ix>
-    std::enable_if_t<sizeof...(Ix) == Ndim, T &> operator()(Ix... index) const {
+    const std::enable_if_t<sizeof...(Ix) == Ndim, T &> operator()(Ix... index) const {
         return buffer_[element_offset(strides_, index...)];
     }
 
@@ -92,13 +85,17 @@ class NDView : public ArrayExpr<NDView<T, Ndim>, Ndim> {
     T *end() { return buffer_ + size_; }
     T const *begin() const { return buffer_; }
     T const *end() const { return buffer_ + size_; }
-    T &operator()(ssize_t i) const { return buffer_[i]; }
-    T &operator[](ssize_t i) const { return buffer_[i]; }
+    T &operator()(ssize_t i)  { return buffer_[i]; }
+    T &operator[](ssize_t i)  { return buffer_[i]; }
+    const T &operator()(ssize_t i) const { return buffer_[i]; }
+    const T &operator[](ssize_t i) const { return buffer_[i]; }
 
     bool operator==(const NDView &other) const {
         if (size_ != other.size_)
             return false;
-        for (uint64_t i = 0; i != size_; ++i) {
+        if (shape_ != other.shape_)
+            return false;
+        for (size_t i = 0; i != size_; ++i) {
             if (buffer_[i] != other.buffer_[i])
                 return false;
         }
@@ -157,6 +154,7 @@ class NDView : public ArrayExpr<NDView<T, Ndim>, Ndim> {
     auto shape(ssize_t i) const { return shape_[i]; }
 
     T *data() { return buffer_; }
+    const T *data() const { return buffer_; }
     void print_all() const;
 
   private:
@@ -180,6 +178,7 @@ class NDView : public ArrayExpr<NDView<T, Ndim>, Ndim> {
         return *this;
     }
 };
+
 template <typename T, ssize_t Ndim> void NDView<T, Ndim>::print_all() const {
     for (auto row = 0; row < shape_[0]; ++row) {
         for (auto col = 0; col < shape_[1]; ++col) {
diff --git a/src/NDView.test.cpp b/src/NDView.test.cpp
index a65758c..04f56dd 100644
--- a/src/NDView.test.cpp
+++ b/src/NDView.test.cpp
@@ -21,6 +21,57 @@ TEST_CASE("Element reference 1D") {
     }
 }
 
+
+TEST_CASE("Assign elements through () and []") {
+    std::vector<int> vec;
+    for (int i = 0; i != 10; ++i) {
+        vec.push_back(i);
+    }
+    NDView<int, 1> data(vec.data(), Shape<1>{10});
+    REQUIRE(vec.size() == static_cast<size_t>(data.size()));
+    
+    data[3] = 187;
+    data(4) = 512;
+
+
+    REQUIRE(data(0) == 0);
+    REQUIRE(data[0] == 0);
+    REQUIRE(data(1) == 1);
+    REQUIRE(data[1] == 1);
+    REQUIRE(data(2) == 2);
+    REQUIRE(data[2] == 2);
+    REQUIRE(data(3) == 187);
+    REQUIRE(data[3] == 187);
+    REQUIRE(data(4) == 512);
+    REQUIRE(data[4] == 512);
+    REQUIRE(data(5) == 5);
+    REQUIRE(data[5] == 5);
+    REQUIRE(data(6) == 6);
+    REQUIRE(data[6] == 6);
+    REQUIRE(data(7) == 7);
+    REQUIRE(data[7] == 7);
+    REQUIRE(data(8) == 8);
+    REQUIRE(data[8] == 8);
+    REQUIRE(data(9) == 9);
+    REQUIRE(data[9] == 9);
+
+
+}
+
+TEST_CASE("Element reference 1D with a const NDView") {
+    std::vector<int> vec;
+    for (int i = 0; i != 10; ++i) {
+        vec.push_back(i);
+    }
+    const NDView<int, 1> data(vec.data(), Shape<1>{10});
+    REQUIRE(vec.size() == static_cast<size_t>(data.size()));
+    for (int i = 0; i != 10; ++i) {
+        REQUIRE(data(i) == vec[i]);
+        REQUIRE(data[i] == vec[i]);
+    }
+}
+
+
 TEST_CASE("Element reference 2D") {
     std::vector<int> vec(12);
     std::iota(vec.begin(), vec.end(), 0);
@@ -56,7 +107,7 @@ TEST_CASE("Element reference 3D") {
     }
 }
 
-TEST_CASE("Plus and miuns with single value") {
+TEST_CASE("Plus and minus with single value") {
     std::vector<int> vec(12);
     std::iota(vec.begin(), vec.end(), 0);
     NDView<int, 2> data(vec.data(), Shape<2>{3, 4});
@@ -137,16 +188,9 @@ TEST_CASE("iterators") {
     }
 }
 
-// TEST_CASE("shape from vector") {
-//     std::vector<int> vec;
-//     for (int i = 0; i != 12; ++i) {
-//         vec.push_back(i);
-//     }
-//     std::vector<ssize_t> shape{3, 4};
-//     NDView<int, 2> data(vec.data(), shape);
-// }
 
-TEST_CASE("divide with another span") {
+
+TEST_CASE("divide with another NDView") {
     std::vector<int> vec0{9, 12, 3};
     std::vector<int> vec1{3, 2, 1};
     std::vector<int> result{3, 6, 3};
@@ -183,6 +227,30 @@ TEST_CASE("compare two views") {
     REQUIRE((view1 == view2));
 }
 
+TEST_CASE("Compare two views with different size"){
+    std::vector<int> vec1(12);
+    std::iota(vec1.begin(), vec1.end(), 0);
+    NDView<int, 2> view1(vec1.data(), Shape<2>{3, 4});
+
+    std::vector<int> vec2(8);
+    std::iota(vec2.begin(), vec2.end(), 0);
+    NDView<int, 2> view2(vec2.data(), Shape<2>{2, 4});
+
+    REQUIRE_FALSE(view1 == view2);
+}
+
+TEST_CASE("Compare two views with same size but different shape"){
+    std::vector<int> vec1(12);
+    std::iota(vec1.begin(), vec1.end(), 0);
+    NDView<int, 2> view1(vec1.data(), Shape<2>{3, 4});
+
+    std::vector<int> vec2(12);
+    std::iota(vec2.begin(), vec2.end(), 0);
+    NDView<int, 2> view2(vec2.data(), Shape<2>{2, 6});
+
+    REQUIRE_FALSE(view1 == view2);
+}
+
 TEST_CASE("Create a view over a vector") {
     std::vector<int> vec(12);
     std::iota(vec.begin(), vec.end(), 0);