add view free memory action (#33)

Author: samuelnguyen999

src/ui_state/view_menu/view_free_memory.py

@@ -2,10 +2,33 @@
 The file to hold the View Free Memory class
 """
 
+from src.devices.library import Keypad
 from src.ui_state.ui_state import UIState
 
 
 class ViewFreeMemory(UIState):
     """
     This is a class for the ViewFreeMemory state of the Tank Controller
     """
+
+    def __init__(self, titrator, previous_state=None):
+        """
+        The constructor for the ViewFreeMemory class
+        """
+        super().__init__(titrator)
+        self.previous_state = previous_state
+
+    def loop(self):
+        """
+        The loop function for the ViewFreeMemory class
+        """
+        free_memory = "3519"
+        self.titrator.lcd.print("Free Memory:", line=1)
+        self.titrator.lcd.print(f"{free_memory} bytes", line=2)
+
+    def handle_key(self, key):
+        """
+        The handle_key function for the ViewFreeMemory class
+        """
+        if key in [Keypad.KEY_4, Keypad.KEY_D]:
+            self._set_next_state(self.previous_state, True)

tests/ui_state/view_menu/view_free_memory_test.py

@@ -0,0 +1,57 @@
+"""
+the file to test the View Free Memory class
+"""
+
+from unittest import mock
+
+from src.devices.library import LiquidCrystal
+from src.titrator import Titrator
+from src.ui_state.main_menu import MainMenu
+from src.ui_state.ui_state import UIState
+from src.ui_state.view_menu.view_free_memory import ViewFreeMemory
+
+
+class MockPreviousState(UIState):
+    """
+    A mock previous state for testing purposes
+    """
+
+    def __init__(self, titrator):
+        super().__init__(titrator)
+
+
+@mock.patch.object(LiquidCrystal, "print")
+def test_view_free_memory(print_mock):
+    """
+    The function to test ViewFreeMemory's loop function
+    """
+    state = ViewFreeMemory(Titrator(), MainMenu(Titrator()))
+
+    state.loop()
+
+    print_mock.assert_any_call("Free Memory:", line=1)
+    print_mock.assert_any_call("3519 bytes", line=2)
+
+
+def test_handle_key_4():
+    """
+    The function to test the back handle key
+    """
+    titrator = Titrator()
+
+    titrator.state = ViewFreeMemory(titrator, MockPreviousState(titrator))
+
+    titrator.state.handle_key("4")
+    assert isinstance(titrator.state, MockPreviousState)
+
+
+def test_handle_key_d():
+    """
+    The function to test the reset handle keys
+    """
+    titrator = Titrator()
+
+    titrator.state = ViewFreeMemory(titrator, MockPreviousState(titrator))
+
+    titrator.state.handle_key("D")
+    assert isinstance(titrator.state, MockPreviousState)