Rewrite tests for valid resolutions

tests/test_valid_resolution.py

@@ -0,0 +1,60 @@
+"""Tests whether validation of resolution specification works as expected
+
+Tests the combined specification of shape (in pixels), visual_size (deg) and ppd.
+If this makes sense, i.e. roughly, int(visual_size * ppd) == shape,
+function should pass without output.
+If it does not make sense, function should raise a ResolutionError.
+
+The tests do this through parameterization:
+pytest runs each test for each of the specified parameter sets.
+
+For the valid-input tests, each parameter set specifies the (valid) input,
+and value (in canonical form) that should be returned.
+If the actual returned value matches this expected return value, the test passes.
+
+For the invalid-input tests, each parameter set specifies the (invalid) input,
+and the function should raise a ResolutionError for each of these.
+"""
+import pytest
+from stimuli.utils import resolution
+
+
+@pytest.mark.parametrize(
+    "shape, visual_size, ppd",
+    (
+        ((1024, 1024), (32, 32), (32, 32)),
+        ((1024, 1024), (32, 16), (32, 64)),
+        ((512, 1024), (16, 64), (32, 16)),
+        ((500, 400), (20, 40), (25, 10)),
+        (1024, (32, 32), (32, 32)),
+        ((1024, 1024), 32, (32, 32)),
+        ((1024, 1024), (32, 32), 32),
+    ),
+)
+def test_valid_resolution(shape, visual_size, ppd):
+    resolution.valid_resolution(shape=shape, visual_size=visual_size, ppd=ppd)
+
+
+@pytest.mark.parametrize(
+    "shape, visual_size, ppd",
+    (
+        ((1024, 1024), (32, 32), (16, 16)),
+        ((1024, 1024), (32, 16), (32, 32)),
+        ((512, 1024), (32, 32), (32, 32)),
+        ((500, 400), (20, 20), (25, 10)),
+        (1024, (32, 16), (32, 32)),
+        ((1024, 512), 32, (32, 30)),
+        ((1024, 512), (32, 32), 32),
+        ((1024, None), (32, 32), (32, 32)),
+        ((1024, 1024), (32, None), (32, 32)),
+        ((1024, 1024), (32, 32), (None, 32)),
+        ((1024, None), (32, 32), (32, 32)),
+        ((1024, 1024), (32, None), (32, 32)),
+        (None, (32, 32), (32, 32)),
+        ((1024, 1024), None, (32, 32)),
+        ((1024, 1024), (32, 32), None),
+    ),
+)
+def test_invalid_resolution(shape, visual_size, ppd):
+    with pytest.raises(resolution.ResolutionError):
+        resolution.valid_resolution(shape=shape, visual_size=visual_size, ppd=ppd)