diff --git a/CMakeLists.txt b/CMakeLists.txt
index 22167ab..526e937 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,11 +5,14 @@ project(Sudoku)
 set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
-set(SOURCE_FILES
+set(LIB_SOURCE_FILES
   solver/cell.cpp
   solver/puzzle.cpp
   solver/solver.cpp
-  solver.cpp
 )
 
-add_executable(solver ${SOURCE_FILES})
+add_library(solver ${LIB_SOURCE_FILES})
+target_include_directories(solver PUBLIC "${PROJECT_SOURCE_DIR}")
+
+add_executable(test_solver solver.cpp)
+target_link_libraries(test_solver PUBLIC solver)
diff --git a/solver/cell.cpp b/solver/cell.cpp
index 38a8bbf..f0339a1 100644
--- a/solver/cell.cpp
+++ b/solver/cell.cpp
@@ -1,4 +1,4 @@
-#include "cell.h"
+#include "solver/cell.h"
 
 #include <algorithm>
 #include <cassert>
diff --git a/solver/puzzle.cpp b/solver/puzzle.cpp
index f77c226..eac6636 100644
--- a/solver/puzzle.cpp
+++ b/solver/puzzle.cpp
@@ -1,4 +1,4 @@
-#include "puzzle.h"
+#include "solver/puzzle.h"
 
 #include <algorithm>
 #include <cassert>
diff --git a/solver/puzzle.h b/solver/puzzle.h
index 9138c69..9c3d7e2 100644
--- a/solver/puzzle.h
+++ b/solver/puzzle.h
@@ -3,7 +3,7 @@
 #include <optional>
 #include <string>
 
-#include "cell.h"
+#include "solver/cell.h"
 
 class Puzzle {
  public:
diff --git a/solver/solver.cpp b/solver/solver.cpp
index ebf74b1..5370f3d 100644
--- a/solver/solver.cpp
+++ b/solver/solver.cpp
@@ -1,4 +1,4 @@
-#include "solver.h"
+#include "solver/solver.h"
 
 #include <sstream>
 
diff --git a/solver/solver.h b/solver/solver.h
index f59bb03..ef66894 100644
--- a/solver/solver.h
+++ b/solver/solver.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include "puzzle.h"
+#include "solver/puzzle.h"
 
 class Solver {
  public: