diff --git a/octa/type_traits.h b/octa/type_traits.h
index 869bc4f..f545748 100644
--- a/octa/type_traits.h
+++ b/octa/type_traits.h
@@ -11,7 +11,7 @@
 #include "octa/types.h"
 
 namespace octa {
-    /* forward declarations */
+/* forward declarations */
 
 namespace detail {
     template<typename> struct RemoveCvBase;
@@ -1172,6 +1172,6 @@ namespace detail {
 
 template<typename T>
 using UnderlyingType = typename octa::detail::UnderlyingTypeBase<T>::Type;
-}
+} /* namespace octa */
 
 #endif
\ No newline at end of file
diff --git a/tests/utility.cpp b/tests/utility.cpp
new file mode 100644
index 0000000..a293914
--- /dev/null
+++ b/tests/utility.cpp
@@ -0,0 +1,91 @@
+#include <assert.h>
+#include <string.h>
+#include "octa/utility.h"
+#include "octa/string.h"
+
+using namespace octa;
+
+struct Foo {
+    int x;
+    Foo(): x(5) {}
+    Foo(int x): x(x) {}
+    Foo(const Foo &x): x(x.x) {}
+    Foo(Foo &&x): x(x.x) { x.x = 0; }
+    Foo &operator=(int _x) {
+        x = _x;
+        return *this;
+    }
+};
+
+struct NotSwappable {
+    int i;
+    NotSwappable(int i): i(i) {}
+};
+
+struct Swappable {
+    int i;
+    bool swapped;
+    Swappable(int i): i(i), swapped(false) {}
+    void swap(Swappable &v) {
+        auto j = i;
+        i = v.i;
+        v.i = j;
+        swapped = v.swapped = true;
+    }
+};
+
+int main() {
+    Foo bar(150);
+    Foo baz(move(bar));
+
+    assert(bar.x == 0);
+    assert(baz.x == 150);
+
+    Foo cp(baz);
+
+    assert(baz.x == 150);
+    assert(cp.x == 150);
+
+    auto i = exchange(baz, 20);
+    assert(baz.x == 20);
+    assert(i.x == 150);
+
+    NotSwappable nsx(10);
+    NotSwappable nsy(20);
+
+    swap(nsx, nsy);
+    assert(nsx.i == 20);
+    assert(nsy.i == 10);
+
+    Swappable sx(10);
+    Swappable sy(20);
+
+    assert(!sx.swapped);
+    assert(!sy.swapped);
+
+    swap(sx, sy);
+    assert(sx.swapped);
+    assert(sy.swapped);
+    assert(sx.i == 20);
+    assert(sy.i == 10);
+
+    int ai[3] = { 5, 10, 15 };
+    int bi[3] = { 6, 11, 16 };
+    swap(ai, bi);
+
+    assert(ai[0] == 6);
+    assert(bi[2] == 15);
+
+    auto x = make_pair(5, 3.14f);
+
+    assert((IsSame<decltype(x.first), int>::value));
+    assert((IsSame<decltype(x.second), float>::value));
+
+    assert(x.first == 5);
+    assert(x.second == 3.14f);
+
+    auto st = make_pair(5, 10);
+    assert(!strcmp(to_string(st).data(), "{5, 10}"));
+
+    return 0;
+}
\ No newline at end of file