adds tests for the elcid.constants data/methods

elcid/test/test_constants.py

@@ -0,0 +1,26 @@
+from opal.core.test import OpalTestCase
+from elcid import constants
+
+
+class ConstantsTestCase(OpalTestCase):
+    def test_expected_constants(self):
+        """
+        We won't test everything, but spot check a simple one
+        """
+        self.assertEqual(
+            constants.LAB_TEST_TAGS["TITANIUM"],
+            ['ALL-TESTS', 'ALLERGY-TESTS', 'OTHER', 'SPECIALITY-ALLERGY']
+        )
+
+    def test_invert_lookups(self):
+        # we test against an iterator as that's what
+        # we use in the file
+        to_invert = dict(a=(i for i in ["b", "c", "d"]))
+        expected = dict(
+            b=["a"],
+            c=["a"],
+            d=["a"],
+        )
+        self.assertEqual(
+            constants.invert_lookups(to_invert), expected
+        )