Add basic read tests (#32)

doc/source/changelog.rst

@@ -5,6 +5,7 @@ Changelog
 
 X.Y.Z (DD-MM-YYYY)
 ------------------
+* Add basic read tests (:pr:`32`)
 * Fix Dataset and DataTree equivalence checks in test cases (:pr:`31`)
 
 0.2.1 (04-10-2024)

tests/test_read.py

@@ -0,0 +1,35 @@
+from functools import reduce
+from operator import mul
+
+import numpy as np
+import pytest
+from numpy.testing import assert_array_equal
+from xarray.backends.api import open_datatree
+
+
+@pytest.mark.parametrize(
+  "simmed_ms",
+  [
+    {
+      "name": "backend.ms",
+      "data_description": [(8, ["XX", "XY", "YX", "YY"]), (4, ["RR", "LL"])],
+    }
+  ],
+  indirect=True,
+)
+def test_basic_read(simmed_ms):
+  """Test for ramp function values produced by simulator"""
+  xdt = open_datatree(simmed_ms)
+
+  for node in xdt.subtree:
+    if "data_description_id" in node.attrs:
+      vis = node.VISIBILITY.values
+      nelements = reduce(mul, vis.shape, 1)
+      expected = np.arange(nelements, dtype=np.float64)
+      expected = (expected + expected * 1j).reshape(vis.shape)
+      assert_array_equal(vis, expected)
+
+      uvw = node.UVW.values
+      nelements = reduce(mul, uvw.shape, 1)
+      expected = np.arange(nelements, dtype=np.float64).reshape(uvw.shape)
+      assert_array_equal(uvw, expected)