From 46cda8d7a5fb90e5d3baf8dde60b8e1994bc29e6 Mon Sep 17 00:00:00 2001
From: Jeremy Muhlich <jmuhlich@bitflood.org>
Date: Tue, 1 Sep 2020 19:39:29 -0400
Subject: [PATCH] Add tests for quantity fields

---
 testing/test_units.py | 62 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 testing/test_units.py

diff --git a/testing/test_units.py b/testing/test_units.py
new file mode 100644
index 00000000..765d6ce0
--- /dev/null
+++ b/testing/test_units.py
@@ -0,0 +1,62 @@
+import pytest
+from pydantic import ValidationError
+from pint import DimensionalityError
+from ome_types.model import Channel, Laser, Plane
+from ome_types.dataclasses import ureg
+
+
+def test_quantity_math():
+    """Validate math on quantities with different but compatible units."""
+    channel = Channel(
+        excitation_wavelength=475,
+        excitation_wavelength_unit="nm",
+        emission_wavelength=530000,
+        emission_wavelength_unit="pm",
+    )
+    shift = (
+        channel.emission_wavelength_quantity - channel.excitation_wavelength_quantity
+    )
+    # Compare to a tolerance due to Pint internal factor representation.
+    assert abs(shift.to("nm").m - 55) < 1e-12
+
+
+def test_invalid_unit():
+    """Ensure incompatible units in constructor raises ValidationError."""
+    with pytest.raises(ValidationError):
+        Channel(
+            excitation_wavelength=475, excitation_wavelength_unit="kg",
+        )
+
+
+def test_dimensionality_error():
+    """Ensure math on incompatible units raises DimensionalityError."""
+    laser = Laser(
+        id="LightSource:1",
+        repetition_rate=10,
+        repetition_rate_unit="MHz",
+        wavelength=640,
+    )
+    with pytest.raises(DimensionalityError):
+        laser.repetition_rate_quantity + laser.wavelength_quantity
+
+
+def test_reference_frame():
+    """Validate reference_frame behavior."""
+    plane = Plane(
+        the_c=0,
+        the_t=0,
+        the_z=0,
+        position_x=1,
+        position_x_unit="reference frame",
+        position_y=2,
+        position_y_unit="mm",
+    )
+    # Verify two different ways that reference_frame and length are incompatible.
+    with pytest.raises(DimensionalityError):
+        plane.position_x_quantity + plane.position_y_quantity
+    product = plane.position_x_quantity * plane.position_y_quantity
+    assert not product.check("[area]")
+    # Verify that we can obtain a usable length if we know the conversion factor.
+    conversion_factor = ureg.Quantity(1, "micron/reference_frame")
+    position_x = plane.position_x_quantity * conversion_factor
+    assert position_x.check("[length]")