Move prepare_<field> to single module and add tests for default parse_mode

tests/test_api/test_methods/test_base.py

@@ -0,0 +1,62 @@
+from typing import Dict, Optional
+
+import pytest
+
+from aiogram import Bot
+from aiogram.api.methods.base import prepare_parse_mode
+
+
+class TestPrepareFile:
+    # TODO: Add tests
+    pass
+
+
+class TestPrepareInputMedia:
+    # TODO: Add tests
+    pass
+
+
+class TestPrepareMediaFile:
+    # TODO: Add tests
+    pass
+
+
+class TestPrepareParseMode:
+    @pytest.mark.parametrize(
+        "parse_mode,data,result",
+        [
+            [None, {}, None],
+            ["HTML", {}, "HTML"],
+            ["Markdown", {}, "Markdown"],
+            [None, {"parse_mode": "HTML"}, "HTML"],
+            ["HTML", {"parse_mode": "HTML"}, "HTML"],
+            ["Markdown", {"parse_mode": "HTML"}, "HTML"],
+        ],
+    )
+    @pytest.mark.asyncio
+    async def test_default_parse_mode(
+        self, parse_mode: str, data: Dict[str, str], result: Optional[str]
+    ):
+        async with Bot(token="42:TEST", parse_mode=parse_mode).context() as bot:
+            assert bot.parse_mode == parse_mode
+            prepare_parse_mode(data)
+            assert data.get("parse_mode") == result
+
+    @pytest.mark.asyncio
+    async def test_list(self):
+        data = [{}] * 2
+        data.append({"parse_mode": "HTML"})
+        async with Bot(token="42:TEST", parse_mode="Markdown").context():
+            prepare_parse_mode(data)
+
+        assert isinstance(data, list)
+        assert len(data) == 3
+        assert all("parse_mode" in item for item in data)
+        assert data[0]["parse_mode"] == "Markdown"
+        assert data[1]["parse_mode"] == "Markdown"
+        assert data[2]["parse_mode"] == "HTML"
+
+    def test_bot_not_in_context(self):
+        data = {}
+        prepare_parse_mode(data)
+        assert "parse_mode" not in data