Feat/add pytest tests (#4)

* feat: add system check

dev_requirements.txt

@@ -0,0 +1 @@
+pytest==8.1.1

src/check_sys.py

@@ -16,25 +16,28 @@ def check_os_system(self):
         """check operating system"""
         if platform != "linux":
             print("Only Linux is supported")
-            return sys.exit(1)
+            sys.exit(1)
+
 
     def check_python_installed(self):
         """check if python is installed"""
         if os.system("python3 --version") != 0:
             print("Python is not installed")
-            return sys.exit(1)
+            sys.exit(1)
+
 
     def check_python_version(self):
         """check python version"""
         if os.system("python3 --version") >= 3.10:
             print("Please use Python 3.10 or higher")
-            return sys.exit(1)
+            sys.exit(1)
+
 
     def check_git_installed(self):
         """check if git is installed"""
         if os.system("git --version") != 0:
             print("Git is not installed")
-            return sys.exit(1)
+            sys.exit(1)
 
     def __str__(self):
-        return "SystemCheck class"
+        return "SystemCheck Class"