Add block icons

tests/test_icons.py

@@ -0,0 +1,31 @@
+import unittest
+import xml.etree.ElementTree as ET
+
+from pathsim.blocks import Block
+
+import pathsim_flight
+
+
+class TestIcons(unittest.TestCase):
+    """Every block of the toolbox has an icon, read by Block.icon()."""
+
+    def test_blocks_have_icons(self):
+        blocks = [
+            obj
+            for obj in vars(pathsim_flight).values()
+            if isinstance(obj, type)
+            and issubclass(obj, Block)
+            and obj.__module__.startswith("pathsim_flight")
+        ]
+        self.assertGreater(len(blocks), 0)
+
+        for cls in blocks:
+            with self.subTest(block=cls.__name__):
+                icon = cls.icon()
+                self.assertIsNotNone(icon)
+                root = ET.fromstring(icon)
+                self.assertEqual(root.get("viewBox"), "0 0 96 64")
+
+
+if __name__ == "__main__":
+    unittest.main()