Use variable names within parametrize for transforms

tests/test_transforms.py

@@ -1,3 +1,5 @@
+import re
+
 import numpy as np
 import pytest
 
@@ -6,7 +8,7 @@
 params_q_to_tth = [
     # UC1: Empty q values, no wavelength, return empty arrays
     (None, np.empty((0)), np.empty((0))),
-    # # UC2: Empty q values, wavelength specified, return empty arrays
+    # UC2: Empty q values, wavelength specified, return empty arrays
     (4 * np.pi, np.empty((0)), np.empty(0)),
     # UC3: User specified valid q values, no wavelength, return empty arrays
     (
@@ -23,8 +25,15 @@
 @pytest.mark.parametrize("wavelength, q, expected_tth", params_q_to_tth)
 def test_q_to_tth(wavelength, q, expected_tth):
 
+    wavelength_warning_emsg = (
+        "No wavelength has been specified. You can continue to use the DiffractionObject, but "
+        "some of its powerful features will not be available. "
+        "To specify a wavelength, if you have do = DiffractionObject(xarray, yarray, 'tth'), "
+        "you may set do.wavelength = 1.54 with the unit in angstroms."
+    )
     if wavelength is None:
-        with pytest.warns(UserWarning, match="INFO: no wavelength has been specified"):
+        with pytest.warns(UserWarning, match=re.escape(wavelength_warning_emsg)):
+            actual_tth = q_to_tth(q, wavelength)
             actual_tth = q_to_tth(q, wavelength)
     else:
         actual_tth = q_to_tth(q, wavelength)
@@ -35,54 +44,54 @@ def test_q_to_tth(wavelength, q, expected_tth):
 params_q_to_tth_bad = [
     # UC1: user specified invalid q values that result in tth > 180 degrees
     (
-        [4 * np.pi, np.array([0.2, 0.4, 0.6, 0.8, 1, 1.2])],
-        [
-            ValueError,
-            "The supplied input array and wavelength will result in an impossible two-theta. "
-            "Please check these values and re-instantiate the DiffractionObject with correct values.",
-        ],
+        4 * np.pi,
+        np.array([0.2, 0.4, 0.6, 0.8, 1, 1.2]),
+        ValueError,
+        "The supplied input array and wavelength will result in an impossible two-theta. "
+        "Please check these values and re-instantiate the DiffractionObject with correct values.",
     ),
     # UC2: user specified a wrong wavelength that result in tth > 180 degrees
     (
-        [100, np.array([0, 0.2, 0.4, 0.6, 0.8, 1])],
-        [
-            ValueError,
-            "The supplied input array and wavelength will result in an impossible two-theta. "
-            "Please check these values and re-instantiate the DiffractionObject with correct values.",
-        ],
+        100,
+        np.array([0, 0.2, 0.4, 0.6, 0.8, 1]),
+        ValueError,
+        "The supplied input array and wavelength will result in an impossible two-theta. "
+        "Please check these values and re-instantiate the DiffractionObject with correct values.",
     ),
 ]
 
 
-@pytest.mark.parametrize("inputs, expected", params_q_to_tth_bad)
-def test_q_to_tth_bad(inputs, expected):
-    with pytest.raises(expected[0], match=expected[1]):
-        q_to_tth(inputs[1], inputs[0])
+@pytest.mark.parametrize("q, wavelength, expected_error_type, expected_error_msg", params_q_to_tth_bad)
+def test_q_to_tth_bad(q, wavelength, expected_error_type, expected_error_msg):
+    with pytest.raises(expected_error_type, match=expected_error_msg):
+        q_to_tth(wavelength, q)
 
 
 params_tth_to_q = [
     # UC0: User specified empty tth values (without wavelength)
-    ([None, np.array([])], np.array([])),
+    (None, np.array([]), np.array([])),
     # UC1: User specified empty tth values (with wavelength)
-    ([4 * np.pi, np.array([])], np.array([])),
+    (4 * np.pi, np.array([]), np.array([])),
     # UC2: User specified valid tth values between 0-180 degrees (without wavelength)
     (
-        [None, np.array([0, 30, 60, 90, 120, 180])],
+        None,
+        np.array([0, 30, 60, 90, 120, 180]),
         np.array([0, 1, 2, 3, 4, 5]),
     ),
     # UC3: User specified valid tth values between 0-180 degrees (with wavelength)
     # expected q values are sin15, sin30, sin45, sin60, sin90
     (
-        [4 * np.pi, np.array([0, 30.0, 60.0, 90.0, 120.0, 180.0])],
+        4 * np.pi,
+        np.array([0, 30.0, 60.0, 90.0, 120.0, 180.0]),
         np.array([0, 0.258819, 0.5, 0.707107, 0.866025, 1]),
     ),
 ]
 
 
-@pytest.mark.parametrize("inputs, expected", params_tth_to_q)
-def test_tth_to_q(inputs, expected):
-    actual = tth_to_q(inputs[1], inputs[0])
-    assert np.allclose(actual, expected)
+@pytest.mark.parametrize("wavelength, tth, expected_q", params_tth_to_q)
+def test_tth_to_q(wavelength, tth, expected_q):
+    actual_q = tth_to_q(tth, wavelength)
+    assert np.allclose(actual_q, expected_q)
 
 
 params_tth_to_q_bad = [