diff --git a/.gitignore b/.gitignore
index ac26aaa..fc53291 100644
--- a/.gitignore
+++ b/.gitignore
@@ -119,4 +119,5 @@ fabric.properties
 *.cubin
 *.fatbin
 
-.idea/
\ No newline at end of file
+.idea/
+*build*/
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 957f3ad..063d631 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,14 +2,20 @@ cmake_minimum_required(VERSION 3.14)
 
 project(Geometry VERSION 0.1 LANGUAGES CXX)
 
+include(FetchContent)
+
 if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
     set_property(GLOBAL PROPERTY USE_FOLDERS ON)
+
+    include(CTest)
+endif ()
+
+if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME OR GEOMETRY_BUILD_TESTING)
+    add_subdirectory(tests)
 endif ()
 
 set(CMAKE_CXX_STANDARD 17)
 
-include(FetchContent)
-
 FetchContent_Declare(
         eigen
         GIT_REPOSITORY https://gitlab.com/libeigen/eigen.git
@@ -17,8 +23,6 @@ FetchContent_Declare(
 )
 FetchContent_MakeAvailable(eigen)
 
-#include_directories(${PROJECT_SOURCE_DIR}/include ${PROJECT_SOURCE_DIR}/Geometry)
-
 add_subdirectory(src)
 
 add_subdirectory(apps)
\ No newline at end of file
diff --git a/apps/CMakeLists.txt b/apps/CMakeLists.txt
index 85887dd..510ff60 100644
--- a/apps/CMakeLists.txt
+++ b/apps/CMakeLists.txt
@@ -1,3 +1,3 @@
 add_executable(app main.cpp)
 
-target_link_libraries(app PUBLIC Eigen3::Eigen Geometry)
+target_link_libraries(app PUBLIC Geometry)
diff --git a/apps/main.cpp b/apps/main.cpp
index e5c5973..0db4e38 100644
--- a/apps/main.cpp
+++ b/apps/main.cpp
@@ -1,5 +1,5 @@
-#include "Geometry/dummy.h"
-#include "main.h"
+#include "Geometry/dummy.hpp"
+#include "main.hpp"
 int main(){
     cout<<"Hello World"<<endl;
     eigenExample();
diff --git a/include/Geometry/dummy.h b/include/Geometry/dummy.h
deleted file mode 100644
index 2abb9d3..0000000
--- a/include/Geometry/dummy.h
+++ /dev/null
@@ -1,10 +0,0 @@
-//
-// Created by nb on 31.12.23.
-//
-
-#ifndef GEOMETRY_DUMMY_H
-#define GEOMETRY_DUMMY_H
-
-void eigenExample();
-
-#endif //GEOMETRY_DUMMY_H
diff --git a/include/Geometry/dummy.hpp b/include/Geometry/dummy.hpp
new file mode 100644
index 0000000..6070c56
--- /dev/null
+++ b/include/Geometry/dummy.hpp
@@ -0,0 +1,10 @@
+//
+// Created by nb on 31.12.23.
+//
+
+#ifndef GEOMETRY_DUMMY_HPP
+#define GEOMETRY_DUMMY_HPP
+
+void eigenExample();
+
+#endif //GEOMETRY_DUMMY_HPP
diff --git a/include/main.h b/include/main.hpp
similarity index 59%
rename from include/main.h
rename to include/main.hpp
index f62e65e..38c9f6a 100644
--- a/include/main.h
+++ b/include/main.hpp
@@ -2,8 +2,8 @@
 // Created by nb on 31.12.23.
 //
 
-#ifndef GEOMETRY_MAIN_H
-#define GEOMETRY_MAIN_H
+#ifndef GEOMETRY_MAIN_HPP
+#define GEOMETRY_MAIN_HPP
 
 #include <iostream>
 #include <Eigen/Dense>
@@ -12,4 +12,4 @@ using namespace std;
 
 int main();
 
-#endif //GEOMETRY_MAIN_H
+#endif //GEOMETRY_MAIN_HPP
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 5362656..ae91b74 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,4 +1,4 @@
-set(HEADER_LIST "${Geometry_SOURCE_DIR}/include/Geometry/dummy.h")
+set(HEADER_LIST "${Geometry_SOURCE_DIR}/include/Geometry/dummy.hpp")
 
 add_library(Geometry dummy.cpp ${HEADER_LIST})
 
diff --git a/src/dummy.cpp b/src/dummy.cpp
index ff09b57..f77543c 100644
--- a/src/dummy.cpp
+++ b/src/dummy.cpp
@@ -1,7 +1,7 @@
 //
 // Created by nb on 31.12.23.
 //
-#include "Geometry/dummy.h"
+#include "Geometry/dummy.hpp"
 #include <Eigen/Dense>
 #include <iostream>
 
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
new file mode 100644
index 0000000..4b916f8
--- /dev/null
+++ b/tests/CMakeLists.txt
@@ -0,0 +1,11 @@
+FetchContent_Declare(
+        catch
+        GIT_REPOSITORY https://github.com/catchorg/Catch2.git
+        GIT_TAG v2.13.6)
+FetchContent_MakeAvailable(catch)
+
+add_executable(testlib testgeometry.cpp)
+
+target_link_libraries(testlib PRIVATE Geometry Catch2::Catch2)
+
+add_test(NAME testlibtest COMMAND testlib)
\ No newline at end of file