Hypothesis property-based testing demo

.gitignore

@@ -21,3 +21,4 @@ venv
 downloaded_files/
 pymodbus.log
 *.lock
+.hypothesis/

pyproject.toml

@@ -61,6 +61,7 @@ development = [
     "build>=1.2.2",
     "codespell>=2.3.0",
     "coverage>=7.6.1",
+    "hypothesis>=6.137.1",
     "mypy>=1.11.2",
     "pylint>=3.3.0",
     "pytest>=8.3.3",
@@ -313,3 +314,4 @@ quote-style = "double"
 indent-style = "space"
 skip-magic-trailing-comma = false
 line-ending = "auto"
+

test/hypothesis_test.py

@@ -0,0 +1,38 @@
+"""Property-based tests for Modbus payload round-trip encoding/decoding with randomized word order."""
+import pytest
+from hypothesis import given, settings
+from hypothesis import strategies as st
+
+from pymodbus.client.mixin import ModbusClientMixin as mixin
+
+
+word_order_strategy = st.one_of(st.just("big"), st.just("little"))
+
+@given(value=st.integers(min_value=-(2**15), max_value=2**15 - 1), word_order=word_order_strategy)
+def test_round_trip_int16(value, word_order):
+    """Test round-trip int16 encoding/decoding with randomized Modbus word order."""
+    regs = mixin.convert_to_registers(value, word_order=word_order, data_type=mixin.DATATYPE.INT16)
+    result = mixin.convert_from_registers(regs, word_order=word_order, data_type=mixin.DATATYPE.INT16)
+    assert result == value
+
+@given(value=st.integers(min_value=0, max_value=2**16 - 1), word_order=word_order_strategy)
+def test_round_trip_uint16(value, word_order):
+    """Test round-trip uint16 encoding/decoding with randomized Modbus word order."""
+    regs = mixin.convert_to_registers(value, word_order=word_order, data_type=mixin.DATATYPE.UINT16)
+    result = mixin.convert_from_registers(regs, word_order=word_order, data_type=mixin.DATATYPE.UINT16)
+    assert result == value
+
+@given(value=st.integers(min_value=-(2**31), max_value=2**31 - 1), word_order=word_order_strategy)
+def test_round_trip_int32(value, word_order):
+    """Test round-trip int32 encoding/decoding with randomized Modbus word order."""
+    regs = mixin.convert_to_registers(value, word_order=word_order, data_type=mixin.DATATYPE.INT32)
+    result = mixin.convert_from_registers(regs, word_order=word_order, data_type=mixin.DATATYPE.INT32)
+    assert result == value
+
+@given(value=st.floats(allow_nan=False, allow_infinity=False, width=64), word_order=word_order_strategy)
+@settings(deadline=None)
+def test_round_trip_float64(value, word_order):
+    """Test round-trip float64 encoding/decoding with randomized Modbus word order."""
+    regs = mixin.convert_to_registers(value, word_order=word_order, data_type=mixin.DATATYPE.FLOAT64)
+    result = mixin.convert_from_registers(regs, word_order=word_order, data_type=mixin.DATATYPE.FLOAT64)
+    assert result == pytest.approx(value, rel=1e-12)