autocal layout first design

apps/autocal/tests/test_units.py

@@ -0,0 +1,73 @@
+"""Unit-to-millimetre conversion.
+
+The reference program carries the bench measurement in a comment::
+
+    # 轴0(X)/轴1(Y) 实测: UNITS=10 时 1000用户单位 = 2mm → 每毫米 5000 脉冲
+    # 当量5 → 1000单位=1mm，不是100单位=1mm
+
+These are the assertions that keep that comment honest.
+"""
+
+from __future__ import annotations
+
+import math
+
+import pytest
+
+from orisys_autocal.motion.units import (
+    PULSES_PER_MM,
+    mm_to_user_units,
+    safe_float,
+    user_units_to_mm,
+)
+
+
+@pytest.mark.parametrize(
+    ("units", "user_units", "expected_mm"),
+    [
+        (10.0, 1000.0, 2.0),  # the measured case from the vendor comment
+        (5.0, 1000.0, 1.0),  # ...and the second one
+        (10.0, 0.0, 0.0),
+        (10.0, 5000.0, 10.0),
+        (10.0, -1000.0, -2.0),  # negative travel must stay negative
+    ],
+)
+def test_conversion_matches_the_bench_measurement(units, user_units, expected_mm):
+    assert user_units_to_mm(user_units, units=units) == pytest.approx(expected_mm)
+
+
+def test_default_units_is_the_platform_value():
+    assert user_units_to_mm(1000.0) == pytest.approx(2.0)
+    assert PULSES_PER_MM == 5000.0
+
+
+def test_conversion_round_trips():
+    for units in (1.0, 5.0, 10.0, 37.5):
+        millimetres = user_units_to_mm(1234.5, units=units)
+        assert mm_to_user_units(millimetres, units=units) == pytest.approx(1234.5)
+
+
+def test_a_zero_or_negative_scale_is_not_a_number():
+    """A bad constant must be visibly unusable, not a plausible number."""
+    assert math.isnan(user_units_to_mm(1000.0, pulses_per_mm=0.0))
+    assert math.isnan(user_units_to_mm(1000.0, pulses_per_mm=-1.0))
+    assert math.isnan(mm_to_user_units(1.0, units=0.0))
+
+
+@pytest.mark.parametrize(
+    "text",
+    ["", "   ", "abc", "1,5", None, "nan", "inf", "-inf"],
+)
+def test_unusable_entries_fall_back(text):
+    assert safe_float(text, 42.0) == 42.0
+
+
+@pytest.mark.parametrize("text", ["0", "0.0", " 0 "])
+def test_zero_falls_back_because_it_would_divide(text):
+    """A pulse equivalent of zero must never reach the controller."""
+    assert safe_float(text, 7.0) == 7.0
+
+
+@pytest.mark.parametrize(("text", "expected"), [("5", 5.0), (" 2.5 ", 2.5), ("-3", -3.0)])
+def test_usable_entries_are_parsed(text, expected):
+    assert safe_float(text, 42.0) == expected