diff --git a/BitBoard.cpp b/BitBoard.cpp
index 6b26519..4c2d793 100644
--- a/BitBoard.cpp
+++ b/BitBoard.cpp
@@ -1,4 +1,4 @@
-#include "BitBoard.h"
+#include "BitBoard.hpp"
 
 BitBoard::BitBoard(uint64_t v) {
     mBoard = v;
diff --git a/BitBoard.h b/BitBoard.hpp
similarity index 98%
rename from BitBoard.h
rename to BitBoard.hpp
index b88cc2d..6ae9fd2 100644
--- a/BitBoard.h
+++ b/BitBoard.hpp
@@ -31,6 +31,9 @@ public:
     explicit constexpr operator bool() const {
         return mBoard != 0;
     }
+    explicit constexpr operator unsigned long() const {
+        return mBoard;
+    }
     explicit constexpr operator unsigned long long() const {
         return mBoard;
     }
diff --git a/Board.hpp b/Board.hpp
index ee9dccb..0680a41 100644
--- a/Board.hpp
+++ b/Board.hpp
@@ -5,7 +5,7 @@
 #include "Square.hpp"
 #include "Move.hpp"
 #include "CastlingRights.hpp"
-#include "BitBoard.h"
+#include "BitBoard.hpp"
 
 #include <optional>
 #include <iosfwd>
diff --git a/Tests/BitBoardTest.cpp b/Tests/BitBoardTest.cpp
new file mode 100644
index 0000000..cd03758
--- /dev/null
+++ b/Tests/BitBoardTest.cpp
@@ -0,0 +1,22 @@
+#include "catch2/catch.hpp"
+
+#include "TestUtils.hpp"
+
+#include "BitBoard.hpp"
+
+#include <set>
+#include <iostream>
+
+TEST_CASE("King attacks are correctly generated", "[Board][Fundamental]") {
+    auto board = BitBoard::fromIndex(G2);
+    board |= BitBoard::fromIndex(B7);
+
+    BitBoard ka = BitBoard::kingAttacks(board);
+    REQUIRE((ka == (
+            BitBoard::fromIndex(G1) | BitBoard::fromIndex(G3) | BitBoard::fromIndex(H1) | BitBoard::fromIndex(H2)
+                    | BitBoard::fromIndex(H3) | BitBoard::fromIndex(F1) | BitBoard::fromIndex(F2)
+                    | BitBoard::fromIndex(F3) |
+                    BitBoard::fromIndex(B8) | BitBoard::fromIndex(B6) | BitBoard::fromIndex(A6)
+                    | BitBoard::fromIndex(A7) | BitBoard::fromIndex(A8) | BitBoard::fromIndex(C6)
+                    | BitBoard::fromIndex(C7) | BitBoard::fromIndex(C8))));
+}
\ No newline at end of file
diff --git a/Tests/CMakeLists.txt b/Tests/CMakeLists.txt
index 9a231f7..94b1b39 100644
--- a/Tests/CMakeLists.txt
+++ b/Tests/CMakeLists.txt
@@ -8,6 +8,7 @@ add_executable(tests
     BoardTests.cpp
     FenTests.cpp
     EngineTests.cpp
+    BitBoardTest.cpp
 )
 
 target_link_libraries(tests cplchess_lib Catch2::Catch2)