diff --git a/SmartManager/App/command.py b/SmartManager/App/command.py
index 47d4016..dfda53a 100644
--- a/SmartManager/App/command.py
+++ b/SmartManager/App/command.py
@@ -47,7 +47,7 @@ def match(self, textrepr: str) -> bool:
         return True
 
     def execute(self, controller):
-        controller.userinterface.show_output("Invaild Command!!")
+        controller.userinterface.show_output("Invalid Command!!")
 
 
 class WelcomeCommand(Command):
diff --git a/tests/test_app.py b/tests/test_app.py
deleted file mode 100644
index c9a9540..0000000
--- a/tests/test_app.py
+++ /dev/null
@@ -1,2 +0,0 @@
-def test_app():
-    assert True
\ No newline at end of file
diff --git a/tests/test_command.py b/tests/test_command.py
new file mode 100644
index 0000000..9b6bc79
--- /dev/null
+++ b/tests/test_command.py
@@ -0,0 +1,28 @@
+# File: tests/test_command.py
+from test_mocking import controller
+from SmartManager.App.command import Command, HelpCommand, QuitCommand, InvalidCommand
+
+def test_empty_command(controller):
+    assert not controller.command.match("")
+
+def test_add_command():
+    Command.add(HelpCommand())
+    assert isinstance(Command.commands[-1], HelpCommand)
+
+def test_help_command_execution(capsys, controller):
+    command = HelpCommand()
+    command.execute(controller)
+    captured = capsys.readouterr()
+    assert "Here is list of valid Commands:\n\n" in captured.out
+    assert "Commands:\n" in captured.out
+
+def test_invalid_command_execution(capsys, controller):
+    command = InvalidCommand()
+    command.execute(controller)
+    captured = capsys.readouterr()
+    assert "Invalid Command!!" in captured.out
+
+def test_quit_command_execution(controller):
+    command = QuitCommand()
+    command.execute(controller)
+    assert not controller.isrunning()
diff --git a/tests/test_controller.py b/tests/test_controller.py
new file mode 100644
index 0000000..5793f60
--- /dev/null
+++ b/tests/test_controller.py
@@ -0,0 +1,29 @@
+# File: tests/test_controller.py
+from test_mocking import controller
+from SmartManager.App.command import HelpCommand, InvalidCommand
+
+def test_get_command_valid_input(controller, monkeypatch):
+    monkeypatch.setattr('builtins.input', lambda _: 'help')
+    cmd = controller.get_command()
+    assert isinstance(cmd, HelpCommand)
+
+def test_get_command_invalid_input(controller, monkeypatch):
+    monkeypatch.setattr('builtins.input', lambda _: 'invalid')
+    cmd = controller.get_command()
+    assert isinstance(cmd, InvalidCommand)
+
+def test_initial_state(controller):
+    assert not controller.isrunning()
+
+def test_run_and_quit(controller):
+    controller.run()
+    assert controller.isrunning()
+
+    controller.quit()
+    assert not controller.isrunning()
+
+def test_welcome_execution(capsys, controller):
+    controller.welcome()
+
+    captured = capsys.readouterr()
+    assert "Welcome To Smart Manager" in captured.out
diff --git a/tests/test_mocking.py b/tests/test_mocking.py
new file mode 100644
index 0000000..c76c87d
--- /dev/null
+++ b/tests/test_mocking.py
@@ -0,0 +1,19 @@
+from SmartManager.App.controller import Controller
+from SmartManager.App.command import Command, CommandInterface
+from SmartManager.App.datahandler import Datahandler
+from SmartManager.App.interface import CLI
+
+import pytest
+
+@pytest.fixture
+def controller():
+    controller = Controller()
+    controller.userinterface = CLI()
+    controller.command = Command()
+    controller.datahandler = Datahandler()
+    return controller
+
+def test_controller(controller):
+    assert isinstance(controller.command, CommandInterface)
+    assert isinstance(controller.userinterface, CLI)
+    assert isinstance(controller.datahandler, Datahandler)
\ No newline at end of file