feat(history): Implement generic HistoryManager and unit tests

tests/test_history.py

@@ -0,0 +1,75 @@
+import pytest
+import time
+from src.history import HistoryManager, HistoryEntry
+
+def test_initial_state():
+ hm = HistoryManager(max_capacity=5)
+ assert hm.can_undo is False
+ assert hm.can_redo is False
+ assert hm.get_history() == []
+
+def test_push_state():
+ hm = HistoryManager(max_capacity=5)
+ hm.push("state1", "action1")
+ assert hm.can_undo is True
+ assert hm.can_redo is False
+ history = hm.get_history()
+ assert len(history) == 1
+ assert history[0]["description"] == "action1"
+
+def test_undo_redo():
+ hm = HistoryManager(max_capacity=5)
+ s0 = "S0"
+ s1 = "S1"
+ s2 = "S2"
+ 
+ # Start at S0, change to S1
+ hm.push(s0, "Initial")
+ # Now at S1, change to S2
+ hm.push(s1, "Action 1")
+ # Now at S2
+ 
+ # Undo Action 1 (go back to S1)
+ entry = hm.undo(s2, "Current at S2")
+ assert entry.state == s1
+ assert entry.description == "Action 1"
+ assert hm.can_undo is True
+ assert hm.can_redo is True
+ 
+ # Undo Initial (go back to S0)
+ entry = hm.undo(s1, "Current at S1")
+ assert entry.state == s0
+ assert entry.description == "Initial"
+ assert hm.can_undo is False
+ assert hm.can_redo is True
+ 
+ # Redo Initial (go back to S1)
+ entry = hm.redo(s0, "Back at S0")
+ assert entry.state == s1
+ assert entry.description == "Current at S1"
+ assert hm.can_undo is True
+ assert hm.can_redo is True
+ 
+ # Redo Action 1 (go back to S2)
+ entry = hm.redo(s1, "Back at S1")
+ assert entry.state == s2
+ assert entry.description == "Current at S2"
+ assert hm.can_undo is True
+ assert hm.can_redo is False
+
+def test_max_capacity():
+ hm = HistoryManager(max_capacity=2)
+ hm.push("S0", "D0")
+ hm.push("S1", "D1")
+ hm.push("S2", "D2")
+ assert len(hm._undo_stack) == 2
+ assert hm._undo_stack[0].description == "D1"
+ assert hm._undo_stack[1].description == "D2"
+
+def test_redo_cleared_on_push():
+ hm = HistoryManager(max_capacity=5)
+ hm.push("S0", "D0")
+ hm.undo("S1", "D1")
+ assert hm.can_redo is True
+ hm.push("S2", "D2")
+ assert hm.can_redo is False