diff --git a/main.py b/main.py
new file mode 100644
index 000000000..dba6fedb7
--- /dev/null
+++ b/main.py
@@ -0,0 +1,3 @@
+from swap_meet.vendor import Vendor
+from swap_meet.item import Item
+
diff --git a/swap_meet/clothing.py b/swap_meet/clothing.py
index b8afdeb1e..a303ddd3b 100644
--- a/swap_meet/clothing.py
+++ b/swap_meet/clothing.py
@@ -1,2 +1,5 @@
-class Clothing:
-    pass
\ No newline at end of file
+from swap_meet.item import Item
+
+class Clothing(Item):
+    def __init__(self, condition = 0):
+        super().__init__(category = "Clothing", condition = condition)
\ No newline at end of file
diff --git a/swap_meet/decor.py b/swap_meet/decor.py
index eab7a9dbe..df5acf6c2 100644
--- a/swap_meet/decor.py
+++ b/swap_meet/decor.py
@@ -1,2 +1,5 @@
-class Decor:
-    pass
\ No newline at end of file
+from swap_meet.item import Item
+
+class Decor(Item):
+    def __init__(self, condition = 0):
+        super().__init__(category = "Decor", condition = condition)
\ No newline at end of file
diff --git a/swap_meet/electronics.py b/swap_meet/electronics.py
index 2f9dff68a..ff73875c1 100644
--- a/swap_meet/electronics.py
+++ b/swap_meet/electronics.py
@@ -1,2 +1,5 @@
-class Electronics:
-    pass
+from swap_meet.item import Item
+
+class Electronics(Item):
+    def __init__(self, condition = 0):
+        super().__init__(category = "Electronics", condition = condition)
\ No newline at end of file
diff --git a/swap_meet/item.py b/swap_meet/item.py
index 560d759c2..975945bfd 100644
--- a/swap_meet/item.py
+++ b/swap_meet/item.py
@@ -1,2 +1,29 @@
+## I attempted to define these variables below in Item instead of globally, 
+## but it made the code less readable, and required calling them with Items.* or self.*
+
+CATEGORIES = {
+    "": "Hello World!",
+    "Clothing": "The finest clothing you could wear.",
+    "Decor": "Something to decorate your space.",
+    "Electronics": "A gadget full of buttons and secrets.",
+}
+
+CONDITION_DESCRIPTORS = {
+    0: "Oof. Are you sure you want this?",
+    1: "Wow. It's pretty bad.",
+    2: "Significant damage.",
+    3: "Needs some love.",
+    4: "Minor signs of wear or damage.",
+    5: "So good it might be a scam.",
+}
+
 class Item:
-    pass
\ No newline at end of file
+    def __init__(self, category = "", condition = 0):
+        self.category = category
+        self.condition = condition
+
+    def __str__(self):
+        return CATEGORIES[self.category]
+
+    def condition_description(self):
+        return CONDITION_DESCRIPTORS[int(self.condition)]
\ No newline at end of file
diff --git a/swap_meet/vendor.py b/swap_meet/vendor.py
index 87302c056..bb824760b 100644
--- a/swap_meet/vendor.py
+++ b/swap_meet/vendor.py
@@ -1,2 +1,95 @@
 class Vendor:
-    pass
\ No newline at end of file
+    def __init__ (self, inventory = None):
+        if not inventory:
+            inventory = []
+            
+        self.inventory = inventory
+
+    def add(self, item): 
+        self.inventory.append(item)
+        return item
+    
+    def remove(self, item):
+        try: 
+            self.inventory.remove(item)
+            return item
+
+        except:
+            return False
+
+    def get_by_category(self, category):
+        items = []
+
+        for item in self.inventory:
+            if item.category == category:
+                items.append(item)
+
+        return items
+
+    def swap_items(self, vendor, my_item, their_item):
+        '''
+        add my item to vendor's inventory
+        remove my item from my inventory
+        add their item to my inventory
+        remove their item from their inventory
+        ---
+        I initially used the above add() and remove() methods, but wanted something a bit more logically streamlined. 
+        Accomplishing the swap of items using a tuple allows for a direct in-place substitution without iterating over the lists.
+        However, I'm not sure if list index() and list remove() have significantly different time complexity - both seem to be O(n).
+        In addition, using this method throws an error if either item is not in the list, 
+        which allows me to return False using try-except, instead of manually checking and returning False.
+        '''
+        try:
+            my_item_index = self.inventory.index(my_item)
+            their_item_index = vendor.inventory.index(their_item)
+
+            swap_items = self.inventory[my_item_index], vendor.inventory[their_item_index]
+            vendor.inventory[their_item_index], self.inventory[my_item_index] = swap_items
+            return True
+
+        except:
+            return False
+
+    def swap_first_item(self, vendor):
+        '''
+        swap the first item between my inventory and vendor's inventory.
+        return false if either inventory is empty.
+        '''
+        try:
+            my_item = self.inventory[0]
+            their_item = vendor.inventory[0]
+            self.swap_items(vendor, my_item, their_item)
+            return True
+
+        except:
+            return False
+    
+    def get_best_by_category(self, category):
+        '''
+        return item with best condition in a given category (returns one item only)
+        if no items match the given category, return None
+        '''
+        condition = -1
+        best_item = None
+        items = self.get_by_category(category)
+
+        for item in items:
+            if item.condition > condition:
+                best_item = item
+                condition = item.condition
+
+        return best_item
+
+    def swap_best_by_category(self, other, my_priority, their_priority):
+        '''
+        swap items with best condition between my preferred category and another vendor's preferred category
+        if no items are in the category in either vendor's inventory, return False
+        '''
+        my_item = self.get_best_by_category(their_priority)
+        their_item = other.get_best_by_category(my_priority)
+
+        if None in (my_item, their_item):
+            return False
+
+        self.swap_items(other, my_item, their_item)
+        return True
\ No newline at end of file
diff --git a/tests/integration_tests/test_wave_01_02_03.py b/tests/integration_tests/test_wave_01_02_03.py
index 9912414da..25707d998 100644
--- a/tests/integration_tests/test_wave_01_02_03.py
+++ b/tests/integration_tests/test_wave_01_02_03.py
@@ -2,7 +2,7 @@
 from swap_meet.vendor import Vendor
 from swap_meet.item import Item
 
-@pytest.mark.skip
+# @pytest.mark.skip
 @pytest.mark.integration_test
 def test_integration_wave_01_02_03():
     # make a vendor  
diff --git a/tests/integration_tests/test_wave_04_05_06.py b/tests/integration_tests/test_wave_04_05_06.py
index 4d0be9909..91b1362b6 100644
--- a/tests/integration_tests/test_wave_04_05_06.py
+++ b/tests/integration_tests/test_wave_04_05_06.py
@@ -4,7 +4,7 @@
 from swap_meet.decor import Decor
 from swap_meet.electronics import Electronics
 
-@pytest.mark.skip
+# @pytest.mark.skip
 @pytest.mark.integration_test
 def test_integration_wave_04_05_06():
     camila = Vendor()
diff --git a/tests/unit_tests/test_wave_01.py b/tests/unit_tests/test_wave_01.py
index 58478ccf9..b7208d659 100644
--- a/tests/unit_tests/test_wave_01.py
+++ b/tests/unit_tests/test_wave_01.py
@@ -2,12 +2,12 @@
 import pytest
 from swap_meet.vendor import Vendor
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_vendor_has_inventory():
     vendor = Vendor()
     assert len(vendor.inventory) == 0
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_vendor_takes_optional_inventory():
     inventory = ["a", "b", "c"]
     vendor = Vendor(inventory=inventory)
@@ -16,7 +16,7 @@ def test_vendor_takes_optional_inventory():
     assert "b" in vendor.inventory
     assert "c" in vendor.inventory
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_adding_to_inventory():
     vendor = Vendor()
     item = "new item"
@@ -27,7 +27,7 @@ def test_adding_to_inventory():
     assert item in vendor.inventory
     assert result == item
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_removing_from_inventory_returns_item():
     item = "item to remove"
     vendor = Vendor(
@@ -40,7 +40,7 @@ def test_removing_from_inventory_returns_item():
     assert item not in vendor.inventory
     assert result == item
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_removing_not_found_is_false():
     item = "item to remove"
     vendor = Vendor(
@@ -49,7 +49,8 @@ def test_removing_not_found_is_false():
 
     result = vendor.remove(item)
 
-    raise Exception("Complete this test according to comments below.")
+    # raise Exception("Complete this test according to comments below.")
     # *********************************************************************
     # ****** Complete Assert Portion of this test **********
     # *********************************************************************
+    assert result == False
diff --git a/tests/unit_tests/test_wave_02.py b/tests/unit_tests/test_wave_02.py
index 3d7060d7c..88d54b6ea 100644
--- a/tests/unit_tests/test_wave_02.py
+++ b/tests/unit_tests/test_wave_02.py
@@ -2,12 +2,12 @@
 from swap_meet.vendor import Vendor
 from swap_meet.item import Item
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_items_have_blank_default_category():
     item = Item()
     assert item.category == ""
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_get_items_by_category():
     item_a = Item(category="clothing")
     item_b = Item(category="electronics")
@@ -23,7 +23,7 @@ def test_get_items_by_category():
     assert item_c in items
     assert item_b not in items
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_get_no_matching_items_by_category():
     item_a = Item(category="clothing")
     item_b = Item(category="clothing")
@@ -34,7 +34,9 @@ def test_get_no_matching_items_by_category():
 
     items = vendor.get_by_category("electronics")
 
-    raise Exception("Complete this test according to comments below.")
+    # raise Exception("Complete this test according to comments below.")
     # *********************************************************************
     # ****** Complete Assert Portion of this test **********
     # *********************************************************************
+
+    assert len(items) == 0
\ No newline at end of file
diff --git a/tests/unit_tests/test_wave_03.py b/tests/unit_tests/test_wave_03.py
index 0300b638f..2d573fa52 100644
--- a/tests/unit_tests/test_wave_03.py
+++ b/tests/unit_tests/test_wave_03.py
@@ -2,7 +2,7 @@
 from swap_meet.vendor import Vendor
 from swap_meet.item import Item
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_item_overrides_to_string():
     item = Item()
 
@@ -10,7 +10,7 @@ def test_item_overrides_to_string():
 
     assert stringified_item == "Hello World!"
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_items_returns_true():
     item_a = Item(category="clothing")
     item_b = Item(category="clothing")
@@ -38,7 +38,7 @@ def test_swap_items_returns_true():
     assert item_b in jolie.inventory
     assert result
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_items_when_my_item_is_missing_returns_false():
     item_a = Item(category="clothing")
     item_b = Item(category="clothing")
@@ -65,7 +65,7 @@ def test_swap_items_when_my_item_is_missing_returns_false():
     assert item_e in jolie.inventory
     assert not result
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_items_when_their_item_is_missing_returns_false():
     item_a = Item(category="clothing")
     item_b = Item(category="clothing")
@@ -92,7 +92,7 @@ def test_swap_items_when_their_item_is_missing_returns_false():
     assert item_e in jolie.inventory
     assert not result
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_items_from_my_empty_returns_false():
     fatimah = Vendor(
         inventory=[]
@@ -112,7 +112,7 @@ def test_swap_items_from_my_empty_returns_false():
     assert len(jolie.inventory) == 2
     assert not result
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_items_from_their_empty_returns_false():
     item_a = Item(category="clothing")
     item_b = Item(category="clothing")
diff --git a/tests/unit_tests/test_wave_04.py b/tests/unit_tests/test_wave_04.py
index 8190a4ebb..4ef21ff8e 100644
--- a/tests/unit_tests/test_wave_04.py
+++ b/tests/unit_tests/test_wave_04.py
@@ -2,7 +2,7 @@
 from swap_meet.vendor import Vendor
 from swap_meet.item import Item
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_first_item_returns_true():
     item_a = Item(category="clothing")
     item_b = Item(category="clothing")
@@ -30,7 +30,7 @@ def test_swap_first_item_returns_true():
     assert item_a in jolie.inventory
     assert result
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_first_item_from_my_empty_returns_false():
     fatimah = Vendor(
         inventory=[]
@@ -48,7 +48,7 @@ def test_swap_first_item_from_my_empty_returns_false():
     assert len(jolie.inventory) == 2
     assert not result
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_first_item_from_their_empty_returns_false():
     item_a = Item(category="clothing")
     item_b = Item(category="clothing")
diff --git a/tests/unit_tests/test_wave_05.py b/tests/unit_tests/test_wave_05.py
index 7abea06cd..fdeb063a9 100644
--- a/tests/unit_tests/test_wave_05.py
+++ b/tests/unit_tests/test_wave_05.py
@@ -3,25 +3,25 @@
 from swap_meet.decor import Decor
 from swap_meet.electronics import Electronics
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_clothing_has_default_category_and_to_str():
     cloth = Clothing()
     assert cloth.category == "Clothing"
     assert str(cloth) == "The finest clothing you could wear."
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_decor_has_default_category_and_to_str():
     decor = Decor()
     assert decor.category == "Decor"
     assert str(decor) == "Something to decorate your space."
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_electronics_has_default_category_and_to_str():
     electronics = Electronics()
     assert electronics.category == "Electronics"
     assert str(electronics) == "A gadget full of buttons and secrets."
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_items_have_condition_as_float():
     items = [
         Clothing(condition=3.5),
@@ -31,7 +31,7 @@ def test_items_have_condition_as_float():
     for item in items:
         assert item.condition == pytest.approx(3.5)
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_items_have_condition_descriptions_that_are_the_same_regardless_of_type():
     items = [
         Clothing(condition=5),
diff --git a/tests/unit_tests/test_wave_06.py b/tests/unit_tests/test_wave_06.py
index 1f7065ab4..c5056368d 100644
--- a/tests/unit_tests/test_wave_06.py
+++ b/tests/unit_tests/test_wave_06.py
@@ -4,7 +4,7 @@
 from swap_meet.decor import Decor
 from swap_meet.electronics import Electronics
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_best_by_category():
     item_a = Clothing(condition=2.0)
     item_b = Decor(condition=2.0)
@@ -20,7 +20,7 @@ def test_best_by_category():
     assert best_item.category == "Clothing"
     assert best_item.condition == pytest.approx(4.0)
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_best_by_category_no_matches_is_none():
     item_a = Decor(condition=2.0)
     item_b = Decor(condition=2.0)
@@ -33,7 +33,7 @@ def test_best_by_category_no_matches_is_none():
 
     assert best_item is None
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_best_by_category_with_duplicates():
     # Arrange
     item_a = Clothing(condition=2.0)
@@ -50,7 +50,7 @@ def test_best_by_category_with_duplicates():
     assert best_item.category == "Clothing"
     assert best_item.condition == pytest.approx(4.0)
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_best_by_category():
     # Arrange
     # me
@@ -76,7 +76,7 @@ def test_swap_best_by_category():
         their_priority="Decor"
     )
 
-    raise Exception("Complete this test according to comments below.")
+    # raise Exception("Complete this test according to comments below.")
     # *********************************************************************
     # ****** Complete Assert Portion of this test **********
     # *********************************************************************
@@ -84,8 +84,13 @@ def test_swap_best_by_category():
     # - That the results is truthy
     # - That tai and jesse's inventories are the correct length
     # - That all the correct items are in tai and jesse's inventories, including the items which were swapped from one vendor to the other
+    assert result == True
+    assert len(tai.inventory) == 3
+    assert len(jesse.inventory) == 3
+    assert item_a and item_b and item_f in tai.inventory
+    assert item_c and item_d and item_e in jesse.inventory
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_best_by_category_reordered():
     # Arrange
     item_a = Decor(condition=2.0)
@@ -109,7 +114,7 @@ def test_swap_best_by_category_reordered():
         their_priority="Decor"
     )
 
-    raise Exception("Complete this test according to comments below.")
+    # raise Exception("Complete this test according to comments below.")
     # *********************************************************************
     # ****** Complete Assert Portion of this test **********
     # *********************************************************************
@@ -117,8 +122,14 @@ def test_swap_best_by_category_reordered():
     # - That result is truthy
     # - That tai and jesse's inventories are the correct length
     # - That all the correct items are in tai and jesse's inventories, and that the items that were swapped are not there
+    assert result == True
+    assert len(tai.inventory) == 3
+    assert len(jesse.inventory) == 3
+    assert item_a and item_b and item_f in tai.inventory
+    assert item_c and item_d and item_e in jesse.inventory
+
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_best_by_category_no_inventory_is_false():
     tai = Vendor(
         inventory=[]
@@ -144,7 +155,7 @@ def test_swap_best_by_category_no_inventory_is_false():
     assert item_b in jesse.inventory
     assert item_c in jesse.inventory
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_best_by_category_no_other_inventory_is_false():
     item_a = Clothing(condition=2.0)
     item_b = Decor(condition=4.0)
@@ -170,7 +181,7 @@ def test_swap_best_by_category_no_other_inventory_is_false():
     assert item_b in tai.inventory
     assert item_c in tai.inventory
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_best_by_category_no_match_is_false():
     # Arrange
     item_a = Decor(condition=2.0)
@@ -194,7 +205,7 @@ def test_swap_best_by_category_no_match_is_false():
         their_priority="Clothing"
     )
 
-    raise Exception("Complete this test according to comments below.")
+    # raise Exception("Complete this test according to comments below.")
     # *********************************************************************
     # ****** Complete Assert Portion of this test **********
     # *********************************************************************
@@ -202,8 +213,13 @@ def test_swap_best_by_category_no_match_is_false():
     # - That result is falsy
     # - That tai and jesse's inventories are the correct length
     # - That all the correct items are in tai and jesse's inventories
+    assert result == False
+    assert len(tai.inventory) == 3
+    assert len(jesse.inventory) == 3
+    assert item_a and item_b and item_c in tai.inventory
+    assert item_f and item_d and item_e in jesse.inventory
 
-@pytest.mark.skip
+# @pytest.mark.skip
 def test_swap_best_by_category_no_other_match_is_false():
     # Arrange
     item_a = Decor(condition=2.0)
@@ -227,7 +243,7 @@ def test_swap_best_by_category_no_other_match_is_false():
         their_priority="Decor"
     )
 
-    raise Exception("Complete this test according to comments below.")
+    # raise Exception("Complete this test according to comments below.")
     # *********************************************************************
     # ****** Complete Assert Portion of this test **********
     # *********************************************************************
@@ -235,3 +251,8 @@ def test_swap_best_by_category_no_other_match_is_false():
     # - That result is falsy
     # - That tai and jesse's inventories are the correct length
     # - That all the correct items are in tai and jesse's inventories
+    assert result == False
+    assert len(tai.inventory) == 3
+    assert len(jesse.inventory) == 3
+    assert item_a and item_b and item_c in tai.inventory
+    assert item_f and item_d and item_e in jesse.inventory