feat: add sync with coverage tool

pyproject.toml

@@ -302,6 +302,9 @@ optimized = [
     "rust-pyspec-glue>=0.0.9,<0.1.0",
     "ethash>=1.1.0,<2",
 ]
+coverage = [
+    "slipcover",
+]
 
 [tool.setuptools.dynamic]
 version = { attr = "ethereum.__version__" }

src/ethereum_spec_tools/get_baseline_cov.py

@@ -0,0 +1,38 @@
+import xml.etree.ElementTree as ET
+import json
+
+
+def parse_coverage_xml(xml_path):
+    tree = ET.parse(xml_path)
+    root = tree.getroot()
+    result = {}
+
+    for cls in root.findall(".//class"):
+        filename = cls.attrib["filename"]
+        lines = cls.find("lines")
+        if lines is None:
+            continue
+        covered = []
+        missing = []
+        for line in lines.findall("line"):
+            num = int(line.attrib["number"])
+            hits = int(line.attrib["hits"])
+            if hits > 0:
+                covered.append(num)
+            else:
+                missing.append(num)
+        result[filename] = {
+            "covered_lines": covered,
+            "missing_lines": missing
+        }
+    return result
+
+
+if __name__ == "__main__":
+    xml_path = ".tox/coverage.xml"
+    out_file = "baseline_coverage.json"
+
+    data = parse_coverage_xml(xml_path)
+    with open(out_file, "w") as f:
+        json.dump(data, f, indent=2)
+    print(f"Wrote {out_file}")