reorganize the library into three folders lib, contrib and core

Write unittests with pytest
Make all functions and method signatures as keyword only arguments

tests/unittests/test_symbol.py

@@ -0,0 +1,53 @@
+from datetime import datetime, timedelta
+
+import pytest
+
+from aiomql.lib.symbol import Symbol
+from aiomql.lib.candle import Candles
+from aiomql.lib.ticks import Ticks
+
+
+class TestSymbol:
+    @pytest.fixture(scope='class', autouse=True)
+    async def btc(self):
+        symbol = Symbol(name='BTCUSD')
+        select = getattr(symbol, 'select', False)
+        if select is False:
+            await symbol.init()
+        return symbol
+
+    async def test_symbol_attributes(self, btc):
+        assert btc.name == 'BTCUSD'
+        assert btc.select is True
+        assert btc.tick is not None
+
+    async def test_volume(self, btc):
+        volume = btc.volume_min - btc.volume_step
+        success, volume = btc.check_volume(volume=volume)
+        assert success is False
+        volume = btc.volume_min + btc.volume_step * 2
+        success, volume = btc.check_volume(volume=volume)
+        assert success is True
+        volume = btc.volume_min + btc.volume_step * 2.5
+        volume = btc.round_off_volume(volume=volume, round_down=True)
+        assert volume == btc.volume_min + btc.volume_step * 2
+
+    async def test_rates(self, btc):
+        start = datetime(year=2023, month=10, day=5)
+        end = start + timedelta(hours=9)
+        rates_from = await btc.copy_rates_from(timeframe=btc.mt5.TIMEFRAME_H1, date_from=start, count=10)
+        assert isinstance(rates_from, Candles)
+        assert len(rates_from) == 10
+        rates_from_pos = await btc.copy_rates_from_pos(timeframe=btc.mt5.TIMEFRAME_H1, count=10, start_position=0)
+        assert isinstance(rates_from_pos, Candles)
+        assert len(rates_from_pos) == 10
+        rates_range = await btc.copy_rates_range(timeframe=btc.mt5.TIMEFRAME_H1, date_from=start, date_to=end)
+        assert isinstance(rates_range, Candles)
+        assert len(rates_range) == 10
+        ticks_from = await btc.copy_ticks_from(date_from=start, count=10)
+        assert isinstance(ticks_from, Ticks)
+        assert len(ticks_from) == 10
+        end = start + timedelta(seconds=20)
+        ticks_from_pos = await btc.copy_ticks_range(date_from=start, date_to=end)
+        assert isinstance(ticks_from_pos, Ticks)
+        assert len(ticks_from_pos) >= 10