diff --git a/README.md b/README.md
index 272081708..808865fe4 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@
 ### Структура проекта
 
 - `praktikum` - пакет, содержащий код программы
-- `tests` - пакет, содержащий тесты, разделенные по классам. Например, `bun_test.py`, `burger_test.py` и т.д.
+- `tests` - пакет, содержащий тесты, разделенные по классам. Например, `test_bun.py`, `test_burger.py` и т.д.
 
 ### Запуск автотестов
 
diff --git a/praktikum/bun.py b/praktikum/bun.py
new file mode 100644
index 000000000..5504bc1f4
--- /dev/null
+++ b/praktikum/bun.py
@@ -0,0 +1,15 @@
+class Bun:
+    """
+    Модель булочки для бургера.
+    Булочке можно дать название и назначить цену.
+    """
+
+    def __init__(self, name: str, price: float):
+        self.name = name
+        self.price = price
+
+    def get_name(self) -> str:
+        return self.name
+
+    def get_price(self) -> float:
+        return self.price
diff --git a/praktikum/burger.py b/praktikum/burger.py
new file mode 100644
index 000000000..a33cc7c4f
--- /dev/null
+++ b/praktikum/burger.py
@@ -0,0 +1,48 @@
+from typing import List
+
+from .bun import Bun
+from .ingredient import Ingredient
+
+
+class Burger:
+    """
+    Модель бургера.
+    Бургер состоит из булочек и ингредиентов (начинка или соус).
+    Ингредиенты можно перемещать и удалять.
+    Можно распечать чек с информацией о бургере.
+    """
+
+    def __init__(self):
+        self.bun = None
+        self.ingredients: List[Ingredient] = []
+
+    def set_buns(self, bun: Bun):
+        self.bun = bun
+
+    def add_ingredient(self, ingredient: Ingredient):
+        self.ingredients.append(ingredient)
+
+    def remove_ingredient(self, index: int):
+        del self.ingredients[index]
+
+    def move_ingredient(self, index: int, new_index: int):
+        self.ingredients.insert(new_index, self.ingredients.pop(index))
+
+    def get_price(self) -> float:
+        price = self.bun.get_price() * 2
+
+        for ingredient in self.ingredients:
+            price += ingredient.get_price()
+
+        return price
+
+    def get_receipt(self) -> str:
+        receipt: List[str] = [f'(==== {self.bun.get_name()} ====)']
+
+        for ingredient in self.ingredients:
+            receipt.append(f'= {str(ingredient.get_type()).lower()} {ingredient.get_name()} =')
+
+        receipt.append(f'(==== {self.bun.get_name()} ====)\n')
+        receipt.append(f'Price: {self.get_price()}')
+
+        return '\n'.join(receipt)
diff --git a/praktikum/database.py b/praktikum/database.py
new file mode 100644
index 000000000..b99c35512
--- /dev/null
+++ b/praktikum/database.py
@@ -0,0 +1,33 @@
+from typing import List
+
+from .bun import Bun
+from .ingredient import Ingredient
+from .ingredient_types import INGREDIENT_TYPE_SAUCE, INGREDIENT_TYPE_FILLING
+
+
+class Database:
+    """
+    Класс с методами по работе с базой данных.
+    """
+
+    def __init__(self):
+        self.buns: List[Bun] = []
+        self.ingredients: List[Ingredient] = []
+
+        self.buns.append(Bun("black bun", 100))
+        self.buns.append(Bun("white bun", 200))
+        self.buns.append(Bun("red bun", 300))
+
+        self.ingredients.append(Ingredient(INGREDIENT_TYPE_SAUCE, "hot sauce", 100))
+        self.ingredients.append(Ingredient(INGREDIENT_TYPE_SAUCE, "sour cream", 200))
+        self.ingredients.append(Ingredient(INGREDIENT_TYPE_SAUCE, "chili sauce", 300))
+
+        self.ingredients.append(Ingredient(INGREDIENT_TYPE_FILLING, "cutlet", 100))
+        self.ingredients.append(Ingredient(INGREDIENT_TYPE_FILLING, "dinosaur", 200))
+        self.ingredients.append(Ingredient(INGREDIENT_TYPE_FILLING, "sausage", 300))
+
+    def available_buns(self) -> List[Bun]:
+        return self.buns
+
+    def available_ingredients(self) -> List[Ingredient]:
+        return self.ingredients
diff --git a/praktikum/ingredient.py b/praktikum/ingredient.py
new file mode 100644
index 000000000..0e50db8a2
--- /dev/null
+++ b/praktikum/ingredient.py
@@ -0,0 +1,20 @@
+class Ingredient:
+    """
+    Модель ингредиента.
+    Ингредиент: начинка или соус.
+    У ингредиента есть тип (начинка или соус), название и цена.
+    """
+
+    def __init__(self, ingredient_type: str, name: str, price: float):
+        self.type = ingredient_type
+        self.name = name
+        self.price = price
+
+    def get_price(self) -> float:
+        return self.price
+
+    def get_name(self) -> str:
+        return self.name
+
+    def get_type(self) -> str:
+        return self.type
diff --git a/praktikum/ingredient_types.py b/praktikum/ingredient_types.py
new file mode 100644
index 000000000..34940ad5d
--- /dev/null
+++ b/praktikum/ingredient_types.py
@@ -0,0 +1,7 @@
+"""
+Перечисление с типами ингредиентов.
+SAUCE – соус
+FILLING – начинка
+"""
+INGREDIENT_TYPE_SAUCE = 'SAUCE'
+INGREDIENT_TYPE_FILLING = 'FILLING'
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 000000000..1fe7b5eb9
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,2 @@
+pytest==8.3.3
+pytest-cov==5.0.0
diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 000000000..afdb0eaaf
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,28 @@
+import os
+import sys
+
+import pytest
+from unittest.mock import Mock
+
+
+# Ensure the project root (where the `praktikum/` package lives) is importable.
+PROJECT_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), '..'))
+if PROJECT_ROOT not in sys.path:
+    sys.path.insert(0, PROJECT_ROOT)
+
+
+@pytest.fixture
+def bun_mock():
+    bun = Mock()
+    bun.get_name.return_value = 'test bun'
+    bun.get_price.return_value = 50.0
+    return bun
+
+
+@pytest.fixture
+def ingredient_mock():
+    ingr = Mock()
+    ingr.get_type.return_value = 'SAUCE'
+    ingr.get_name.return_value = 'hot sauce'
+    ingr.get_price.return_value = 10.0
+    return ingr
diff --git a/tests/test_bun.py b/tests/test_bun.py
new file mode 100644
index 000000000..7c9b7ff03
--- /dev/null
+++ b/tests/test_bun.py
@@ -0,0 +1,34 @@
+import pytest
+
+from praktikum.bun import Bun
+
+
+@pytest.mark.parametrize(
+    'name',
+    [
+        'black bun',
+        'булочка',
+        'bun-123',
+        'bun!@#$',
+    ],
+)
+def test_get_name_returns_init_value(name):
+    bun = Bun(name, 100.0)
+
+    assert bun.get_name() == name
+
+
+@pytest.mark.parametrize(
+    'price',
+    [
+        0,
+        1,
+        200.5,
+        1_000_000.0,
+        -10.5,
+    ],
+)
+def test_get_price_returns_init_value(price):
+    bun = Bun('black bun', price)
+
+    assert bun.get_price() == price
diff --git a/tests/test_burger.py b/tests/test_burger.py
new file mode 100644
index 000000000..457654360
--- /dev/null
+++ b/tests/test_burger.py
@@ -0,0 +1,82 @@
+from unittest.mock import Mock
+
+import pytest
+
+from praktikum.burger import Burger
+
+
+def test_set_buns_sets_bun_reference(bun_mock):
+    burger = Burger()
+
+    burger.set_buns(bun_mock)
+
+    assert burger.bun is bun_mock
+
+
+def test_add_ingredient_appends_to_list(ingredient_mock):
+    burger = Burger()
+
+    burger.add_ingredient(ingredient_mock)
+
+    assert burger.ingredients == [ingredient_mock]
+
+
+def test_remove_ingredient_deletes_by_index():
+    burger = Burger()
+    ing1, ing2 = Mock(), Mock()
+    burger.ingredients = [ing1, ing2]
+
+    burger.remove_ingredient(0)
+
+    assert burger.ingredients == [ing2]
+
+
+def test_move_ingredient_reorders_list():
+    burger = Burger()
+    ing1, ing2, ing3 = Mock(), Mock(), Mock()
+    burger.ingredients = [ing1, ing2, ing3]
+
+    burger.move_ingredient(0, 2)
+
+    assert burger.ingredients == [ing2, ing3, ing1]
+
+
+def test_get_price_sums_bun_double_and_ingredients(bun_mock):
+    burger = Burger()
+    burger.set_buns(bun_mock)
+
+    ing1, ing2 = Mock(), Mock()
+    ing1.get_price.return_value = 10.0
+    ing2.get_price.return_value = 15.5
+    burger.ingredients = [ing1, ing2]
+
+    assert burger.get_price() == 50.0 * 2 + 10.0 + 15.5
+
+
+def test_get_receipt_formats_lines_and_uses_lowercase_types(bun_mock):
+    burger = Burger()
+    burger.set_buns(bun_mock)
+
+    sauce = Mock()
+    sauce.get_type.return_value = 'SAUCE'
+    sauce.get_name.return_value = 'hot sauce'
+    sauce.get_price.return_value = 10.0
+
+    filling = Mock()
+    filling.get_type.return_value = 'FILLING'
+    filling.get_name.return_value = 'cutlet'
+    filling.get_price.return_value = 20.0
+
+    burger.ingredients = [sauce, filling]
+
+    receipt = burger.get_receipt()
+
+    expected = (
+        '(==== test bun ====)\n'
+        '= sauce hot sauce =\n'
+        '= filling cutlet =\n'
+        '(==== test bun ====)\n\n'
+        'Price: 130.0'
+    )
+
+    assert receipt == expected
diff --git a/tests/test_database.py b/tests/test_database.py
new file mode 100644
index 000000000..e60f13707
--- /dev/null
+++ b/tests/test_database.py
@@ -0,0 +1,34 @@
+from praktikum.database import Database
+from praktikum.bun import Bun
+from praktikum.ingredient import Ingredient
+from praktikum.ingredient_types import INGREDIENT_TYPE_SAUCE, INGREDIENT_TYPE_FILLING
+
+
+def test_available_buns_returns_list_of_buns():
+    db = Database()
+
+    buns = db.available_buns()
+
+    assert isinstance(buns, list)
+    assert buns, 'Ожидался непустой список булочек'
+    assert all(isinstance(bun, Bun) for bun in buns)
+
+    # Проверяем, что возвращаемые объекты можно корректно использовать через публичные методы
+    for bun in buns:
+        assert isinstance(bun.get_name(), str)
+        assert isinstance(bun.get_price(), (int, float))
+
+
+def test_available_ingredients_returns_list_of_ingredients():
+    db = Database()
+
+    ingredients = db.available_ingredients()
+
+    assert isinstance(ingredients, list)
+    assert ingredients, 'Ожидался непустой список ингредиентов'
+    assert all(isinstance(ingredient, Ingredient) for ingredient in ingredients)
+
+    for ingredient in ingredients:
+        assert ingredient.get_type() in (INGREDIENT_TYPE_SAUCE, INGREDIENT_TYPE_FILLING)
+        assert isinstance(ingredient.get_name(), str)
+        assert isinstance(ingredient.get_price(), (int, float))
diff --git a/tests/test_ingredient.py b/tests/test_ingredient.py
new file mode 100644
index 000000000..3d309c346
--- /dev/null
+++ b/tests/test_ingredient.py
@@ -0,0 +1,48 @@
+import pytest
+
+from praktikum.ingredient import Ingredient
+from praktikum.ingredient_types import INGREDIENT_TYPE_SAUCE, INGREDIENT_TYPE_FILLING
+
+
+@pytest.mark.parametrize(
+    'ingredient_type',
+    [
+        INGREDIENT_TYPE_SAUCE,
+        INGREDIENT_TYPE_FILLING,
+    ],
+)
+def test_get_type_returns_init_value(ingredient_type):
+    ingredient = Ingredient(ingredient_type, 'test ingredient', 100.0)
+
+    assert ingredient.get_type() == ingredient_type
+
+
+@pytest.mark.parametrize(
+    'name',
+    [
+        'hot sauce',
+        'котлета',
+        'ingredient-123',
+        'ingr!@#$',
+    ],
+)
+def test_get_name_returns_init_value(name):
+    ingredient = Ingredient(INGREDIENT_TYPE_SAUCE, name, 100.0)
+
+    assert ingredient.get_name() == name
+
+
+@pytest.mark.parametrize(
+    'price',
+    [
+        0,
+        1,
+        300.5,
+        1_000_000.0,
+        -10.5,
+    ],
+)
+def test_get_price_returns_init_value(price):
+    ingredient = Ingredient(INGREDIENT_TYPE_SAUCE, 'test ingredient', price)
+
+    assert ingredient.get_price() == price