add Bot.download_file aliases ability to save files to a directory and automatically create directories (#694)

* add destination_dir and make_dirs parameters to bot download aliases

* add the ability to save files to a directory with path completion based on file_path,
* add an option to automatically create directories in the file path

* Downloadable mixin uses directory creation parameter in bot methods

tests/test_bot/test_bot_download_file.py

@@ -0,0 +1,78 @@
+import os
+from io import BytesIO
+from pathlib import Path
+
+import pytest
+
+from aiogram import Bot
+from aiogram.types import File
+from tests import TOKEN
+from tests.types.dataset import FILE
+
+pytestmark = pytest.mark.asyncio
+
+
+@pytest.fixture(name='bot')
+async def bot_fixture():
+    async def get_file():
+        return File(**FILE)
+
+    """ Bot fixture """
+    _bot = Bot(TOKEN)
+    _bot.get_file = get_file
+    yield _bot
+    await _bot.session.close()
+
+
+@pytest.fixture
+def file():
+    return File(**FILE)
+
+
+@pytest.fixture
+def tmppath(tmpdir, request):
+    os.chdir(tmpdir)
+    yield Path(tmpdir)
+    os.chdir(request.config.invocation_dir)
+
+
+class TestBotDownload:
+    async def test_download_file(self, tmppath, bot, file):
+        f = await bot.download_file(file_path=file.file_path)
+        assert len(f.read()) != 0
+
+    async def test_download_file_destination(self, tmppath, bot, file):
+        await bot.download_file(file_path=file.file_path, destination="test.file")
+        assert os.path.isfile(tmppath.joinpath('test.file'))
+
+    async def test_download_file_destination_with_dir(self, tmppath, bot, file):
+        await bot.download_file(file_path=file.file_path,
+                                destination=os.path.join('dir_name', 'file_name'))
+        assert os.path.isfile(tmppath.joinpath('dir_name', 'file_name'))
+
+    async def test_download_file_destination_raise_file_not_found(self, tmppath, bot, file):
+        with pytest.raises(FileNotFoundError):
+            await bot.download_file(file_path=file.file_path,
+                                    destination=os.path.join('dir_name', 'file_name'),
+                                    make_dirs=False)
+
+    async def test_download_file_destination_io_bytes(self, tmppath, bot, file):
+        f = BytesIO()
+        await bot.download_file(file_path=file.file_path,
+                                destination=f)
+        assert len(f.read()) != 0
+
+    async def test_download_file_raise_value_error(self, tmppath, bot, file):
+        with pytest.raises(ValueError):
+            await bot.download_file(file_path=file.file_path, destination="a", destination_dir="b")
+
+    async def test_download_file_destination_dir(self, tmppath, bot, file):
+        await bot.download_file(file_path=file.file_path, destination_dir='test_dir')
+        assert os.path.isfile(tmppath.joinpath('test_dir', file.file_path))
+
+    async def test_download_file_destination_dir_raise_file_not_found(self, tmppath, bot, file):
+        with pytest.raises(FileNotFoundError):
+            await bot.download_file(file_path=file.file_path,
+                                    destination_dir='test_dir',
+                                    make_dirs=False)
+            assert os.path.isfile(tmppath.joinpath('test_dir', file.file_path))