Add inventory persistence test - PASSES ✅

Test verifies:
- Buy rope → inventory updated, gold deducted
- Rope persists in inventory between commands
- Sell rope → inventory updated, gold increased

Findings:
- Inventory persistence works correctly in core systems
- Issue was shop reality check requiring merchant NPCs
- No bugs in CharacterState.inventory or GameMaster session

This isolates the Playwright test issue to Gradio/web layer

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/test_inventory_persistence.py

@@ -0,0 +1,138 @@
+"""
+Test inventory persistence across multiple commands.
+
+This test verifies that items added to character_state.inventory
+are properly maintained between multiple GM interactions.
+"""
+
+import sys
+from pathlib import Path
+sys.path.insert(0, str(Path(__file__).parent.parent))
+
+from dnd_rag_system.core.chroma_manager import ChromaDBManager
+from dnd_rag_system.systems.gm_dialogue_unified import GameMaster
+from dnd_rag_system.systems.game_state import CharacterState
+
+
+def test_inventory_persistence_across_commands():
+    """
+    Test that inventory persists correctly across multiple GM commands.
+
+    Simulates:
+    1. Create character with initial inventory
+    2. Buy rope (adds to inventory)
+    3. Verify rope is in inventory
+    4. Sell rope (removes from inventory)
+    5. Verify rope is NOT in inventory
+    """
+    print("\n" + "=" * 80)
+    print("TEST: Inventory Persistence Across Commands")
+    print("=" * 80)
+
+    # Initialize systems
+    db = ChromaDBManager()
+    gm = GameMaster(db)
+
+    # Create character state with initial inventory
+    char_state = CharacterState(
+        character_name="Test Hero",
+        max_hp=30,
+        level=3,
+        gold=100
+    )
+    char_state.armor_class = 15
+
+    # Set initial equipment (simulating Thorin's setup)
+    char_state.inventory = {
+        'Longsword': 1,
+        'Shield': 1,
+        'Plate Armor': 1,
+        'Backpack': 1
+    }
+
+    # Attach character to GM session
+    gm.session.character_state = char_state
+    gm.set_context("Test Hero is in a marketplace")
+    gm.set_location("The Market Square", "A bustling marketplace")
+
+    # CRITICAL: Add merchant NPCs to enable shop transactions
+    # The shop system requires either has_shop=True on location OR merchant NPCs present
+    gm.session.npcs_present = ['Merchant', 'Shopkeeper']
+    print(f"   Added NPCs for shop: {gm.session.npcs_present}")
+
+    print(f"\n1️⃣ Initial Setup:")
+    print(f"   Character: {char_state.character_name}")
+    print(f"   Gold: {char_state.gold} GP")
+    print(f"   Inventory: {char_state.inventory}")
+    print(f"   Session character_state ID: {id(char_state)}")
+    print(f"   GM session character_state ID: {id(gm.session.character_state)}")
+
+    # Verify they're the same object
+    assert gm.session.character_state is char_state, "Session character_state should be same object"
+    print("   ✅ Character state attached correctly")
+
+    # Step 2: Buy rope
+    print(f"\n2️⃣ Buying rope...")
+    buy_response = gm.generate_response("/buy rope", use_rag=False)
+
+    print(f"   Response: {buy_response[:200]}...")
+    print(f"   Gold after buy: {gm.session.character_state.gold} GP")
+    print(f"   Inventory after buy: {gm.session.character_state.inventory}")
+
+    # Verify purchase
+    assert "rope" in gm.session.character_state.inventory, "Rope should be in inventory after purchase"
+    assert gm.session.character_state.inventory["rope"] == 1, "Should have 1 rope"
+    assert gm.session.character_state.gold == 99, f"Expected 99 GP, got {gm.session.character_state.gold}"
+    print("   ✅ Rope successfully purchased and added to inventory")
+
+    # CRITICAL: Check if character_state object changed
+    print(f"   Session character_state ID after buy: {id(gm.session.character_state)}")
+    if id(gm.session.character_state) != id(char_state):
+        print("   ⚠️  WARNING: character_state object was replaced!")
+        char_state = gm.session.character_state  # Update reference
+
+    # Step 3: Verify rope persists before selling
+    print(f"\n3️⃣ Checking inventory before sell:")
+    print(f"   Inventory: {gm.session.character_state.inventory}")
+    assert "rope" in gm.session.character_state.inventory, "Rope should still be in inventory"
+    print("   ✅ Rope persisted in inventory")
+
+    # Step 4: Sell rope
+    print(f"\n4️⃣ Selling rope...")
+    sell_response = gm.generate_response("/sell rope", use_rag=False)
+
+    print(f"   Response: {sell_response[:200]}...")
+    print(f"   Gold after sell: {gm.session.character_state.gold} GP")
+    print(f"   Inventory after sell: {gm.session.character_state.inventory}")
+
+    # Verify sale
+    assert "rope" not in gm.session.character_state.inventory, "Rope should NOT be in inventory after sale"
+    assert gm.session.character_state.gold == 99.5, f"Expected 99.5 GP (sold for 0.5), got {gm.session.character_state.gold}"
+    print("   ✅ Rope successfully sold and removed from inventory")
+
+    # Step 5: Final verification
+    print(f"\n5️⃣ Final State:")
+    print(f"   Gold: {gm.session.character_state.gold} GP")
+    print(f"   Inventory: {gm.session.character_state.inventory}")
+    print(f"   Session character_state ID: {id(gm.session.character_state)}")
+
+    print("\n" + "=" * 80)
+    print("✅ ALL INVENTORY PERSISTENCE TESTS PASSED!")
+    print("=" * 80)
+
+    return True
+
+
+if __name__ == "__main__":
+    try:
+        test_inventory_persistence_across_commands()
+    except AssertionError as e:
+        print(f"\n❌ TEST FAILED: {e}")
+        import traceback
+        traceback.print_exc()
+        sys.exit(1)
+    except Exception as e:
+        print(f"\n❌ TEST ERROR: {e}")
+        import traceback
+        traceback.print_exc()
+        sys.exit(1)