import unittest

from modbus_codec import encode_registers


class ModbusCodecTest(unittest.TestCase):
    def test_encode_int16(self):
        self.assertEqual(encode_registers(1, "int16"), [1])
        self.assertEqual(encode_registers(-1, "int16"), [0xFFFF])

    def test_encode_int32_abcd(self):
        self.assertEqual(encode_registers(0x12345678, "int32"), [0x1234, 0x5678])

    def test_encode_float32_abcd(self):
        self.assertEqual(encode_registers(1.0, "float32"), [0x3F80, 0x0000])

    def test_encode_invalid_type(self):
        with self.assertRaises(ValueError):
            encode_registers(1, "uint16")


if __name__ == "__main__":
    unittest.main()