Add unit tests for KLayout-related Python utilities

34 mock-based tests that run without KLayout installed:
- test_generate_klayout_tech.py: .lyt generation including validation
  against real platform templates (nangate45, asap7, sky130hd)
- test_def2stream.py: cell clearing, VIA_ preservation, orphan
  detection, GDS_ALLOW_EMPTY regex, seal file merging, error counting
- test_convertDrc.py: DRC report conversion (box/edge/text violations,
  waived items, comment assembly)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>

Author: oharboe

flow/test/test_convertDrc.py

@@ -0,0 +1,255 @@
+#!/usr/bin/env python3
+
+import unittest
+from unittest.mock import MagicMock, patch
+import sys
+import os
+
+# Mock pya before importing convertDrc since it imports pya at module level
+sys.modules["pya"] = MagicMock()
+
+sys.path.append(os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "util"))
+
+# convertDrc uses a global `in_drc` set by klayout -rd, so we must set it
+import builtins
+
+builtins.in_drc = "/tmp/test.drc"
+builtins.out_file = "/tmp/test.json"
+
+# Now we can import - but the module-level code tries to use pya.Application
+# We need to handle this by patching before import
+import importlib
+
+# Import just the convert_drc function by reading the source
+import types
+
+_util_dir = os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "util")
+_src_path = os.path.join(_util_dir, "convertDrc.py")
+
+# Load only the convert_drc function, not the module-level klayout code
+with open(_src_path) as f:
+    source = f.read()
+
+# Extract just the function definition
+import textwrap
+import re as _re
+
+# Parse out the convert_drc function
+_func_start = source.index("def convert_drc(rdb):")
+_func_end = source.index("\n\napp = pya.Application")
+_func_source = source[_func_start:_func_end]
+
+# Create a module with just the function
+_mod = types.ModuleType("convertDrc_test")
+_mod.__dict__["os"] = os
+_mod.__dict__["in_drc"] = "/tmp/test.drc"
+exec(compile(_func_source, _src_path, "exec"), _mod.__dict__)
+convert_drc = _mod.convert_drc
+
+
+def make_mock_point(x, y):
+    p = MagicMock()
+    p.x = x
+    p.y = y
+    return p
+
+
+def make_mock_edge(p1_x, p1_y, p2_x, p2_y):
+    edge = MagicMock()
+    edge.p1 = make_mock_point(p1_x, p1_y)
+    edge.p2 = make_mock_point(p2_x, p2_y)
+    return edge
+
+
+def make_box_value(left, bottom, right, top):
+    value = MagicMock()
+    value.is_box.return_value = True
+    value.is_edge.return_value = False
+    value.is_edge_pair.return_value = False
+    value.is_polygon.return_value = False
+    value.is_path.return_value = False
+    value.is_text.return_value = False
+    value.is_string.return_value = False
+    box = MagicMock()
+    box.left = left
+    box.bottom = bottom
+    box.right = right
+    box.top = top
+    value.box.return_value = box
+    return value
+
+
+def make_edge_value(p1_x, p1_y, p2_x, p2_y):
+    value = MagicMock()
+    value.is_box.return_value = False
+    value.is_edge.return_value = True
+    value.is_edge_pair.return_value = False
+    value.is_polygon.return_value = False
+    value.is_path.return_value = False
+    value.is_text.return_value = False
+    value.is_string.return_value = False
+    value.edge.return_value = make_mock_edge(p1_x, p1_y, p2_x, p2_y)
+    return value
+
+
+def make_text_value(text):
+    value = MagicMock()
+    value.is_box.return_value = False
+    value.is_edge.return_value = False
+    value.is_edge_pair.return_value = False
+    value.is_polygon.return_value = False
+    value.is_path.return_value = False
+    value.is_text.return_value = True
+    value.is_string.return_value = False
+    value.text.return_value = text
+    return value
+
+
+def make_mock_item(values, is_visited=False, tags_str="", comment=None):
+    item = MagicMock()
+    item.is_visited.return_value = is_visited
+    item.tags_str = tags_str
+    item.each_value.return_value = iter(values)
+    if comment is not None:
+        item.comment = comment
+    else:
+        # Remove hasattr for comment
+        del item.comment
+    return item
+
+
+def make_mock_category(name, description, rdb_id, num_items, items):
+    cat = MagicMock()
+    cat.name.return_value = name
+    cat.description = description
+    cat.rdb_id.return_value = rdb_id
+    cat.num_items.return_value = num_items
+    return cat, items
+
+
+class TestConvertDrc(unittest.TestCase):
+    def test_empty_rdb(self):
+        rdb = MagicMock()
+        rdb.each_category.return_value = iter([])
+
+        result = convert_drc(rdb)
+
+        self.assertEqual(result["source"], os.path.abspath("/tmp/test.drc"))
+        self.assertEqual(result["category"], {})
+
+    def test_empty_category_skipped(self):
+        cat = MagicMock()
+        cat.num_items.return_value = 0
+
+        rdb = MagicMock()
+        rdb.each_category.return_value = iter([cat])
+
+        result = convert_drc(rdb)
+        self.assertEqual(result["category"], {})
+
+    def test_box_violation(self):
+        box_val = make_box_value(100, 200, 300, 400)
+        item = make_mock_item([box_val])
+
+        cat = MagicMock()
+        cat.name.return_value = "metal1.min_width"
+        cat.description = "Minimum width violation"
+        cat.rdb_id.return_value = 1
+        cat.num_items.return_value = 1
+
+        rdb = MagicMock()
+        rdb.each_category.return_value = iter([cat])
+        rdb.each_item_per_category.return_value = iter([item])
+
+        result = convert_drc(rdb)
+
+        violations = result["category"]["metal1.min_width"]["violations"]
+        self.assertEqual(len(violations), 1)
+        self.assertEqual(len(violations[0]["shape"]), 1)
+        shape = violations[0]["shape"][0]
+        self.assertEqual(shape["type"], "box")
+        self.assertEqual(shape["points"][0], {"x": 100, "y": 200})
+        self.assertEqual(shape["points"][1], {"x": 300, "y": 400})
+
+    def test_edge_violation(self):
+        edge_val = make_edge_value(10, 20, 30, 40)
+        item = make_mock_item([edge_val])
+
+        cat = MagicMock()
+        cat.name.return_value = "metal1.spacing"
+        cat.description = "Spacing violation"
+        cat.rdb_id.return_value = 2
+        cat.num_items.return_value = 1
+
+        rdb = MagicMock()
+        rdb.each_category.return_value = iter([cat])
+        rdb.each_item_per_category.return_value = iter([item])
+
+        result = convert_drc(rdb)
+
+        violations = result["category"]["metal1.spacing"]["violations"]
+        shape = violations[0]["shape"][0]
+        self.assertEqual(shape["type"], "line")
+        self.assertEqual(shape["points"][0], {"x": 10, "y": 20})
+        self.assertEqual(shape["points"][1], {"x": 30, "y": 40})
+
+    def test_waived_violation(self):
+        box_val = make_box_value(0, 0, 10, 10)
+        item = make_mock_item([box_val], tags_str="waived")
+
+        cat = MagicMock()
+        cat.name.return_value = "rule1"
+        cat.description = "Rule 1"
+        cat.rdb_id.return_value = 1
+        cat.num_items.return_value = 1
+
+        rdb = MagicMock()
+        rdb.each_category.return_value = iter([cat])
+        rdb.each_item_per_category.return_value = iter([item])
+
+        result = convert_drc(rdb)
+
+        violation = result["category"]["rule1"]["violations"][0]
+        self.assertTrue(violation["waived"])
+
+    def test_text_in_comment(self):
+        text_val = make_text_value("error detail")
+        item = make_mock_item([text_val])
+
+        cat = MagicMock()
+        cat.name.return_value = "rule1"
+        cat.description = "Rule 1"
+        cat.rdb_id.return_value = 1
+        cat.num_items.return_value = 1
+
+        rdb = MagicMock()
+        rdb.each_category.return_value = iter([cat])
+        rdb.each_item_per_category.return_value = iter([item])
+
+        result = convert_drc(rdb)
+
+        violation = result["category"]["rule1"]["violations"][0]
+        self.assertEqual(violation["comment"], "error detail")
+
+    def test_comment_with_text(self):
+        text_val = make_text_value("extra info")
+        item = make_mock_item([text_val], comment="base comment")
+
+        cat = MagicMock()
+        cat.name.return_value = "rule1"
+        cat.description = "Rule 1"
+        cat.rdb_id.return_value = 1
+        cat.num_items.return_value = 1
+
+        rdb = MagicMock()
+        rdb.each_category.return_value = iter([cat])
+        rdb.each_item_per_category.return_value = iter([item])
+
+        result = convert_drc(rdb)
+
+        violation = result["category"]["rule1"]["violations"][0]
+        self.assertEqual(violation["comment"], "base comment: extra info")
+
+
+if __name__ == "__main__":
+    unittest.main()