Refactor tests (better grouping + cocotb support) (#15)

* initial refactor

* fix cocotb tests

* fix typecheck

* install verilator

tests/conftest.py

@@ -0,0 +1,60 @@
+"""Pytest fixtures for unit tests."""
+
+from __future__ import annotations
+
+collect_ignore_glob = ["cocotb/*/smoke/test_register_access.py"]
+
+import os
+from collections.abc import Callable
+from pathlib import Path
+from tempfile import NamedTemporaryFile
+
+import pytest
+from systemrdl import RDLCompileError, RDLCompiler  # type:ignore
+from systemrdl.node import AddrmapNode
+
+_SHIM_DIR = Path(__file__).resolve().parents[1] / "tools" / "shims"
+os.environ["PATH"] = f"{_SHIM_DIR}{os.pathsep}{os.environ.get('PATH', '')}"
+
+
+@pytest.fixture
+def compile_rdl(tmp_path: Path) -> Callable[..., AddrmapNode]:
+    """Compile inline SystemRDL source and return the elaborated root node.
+
+    Parameters
+    ----------
+    tmp_path:
+        Temporary directory provided by pytest.
+    """
+
+    def _compile(
+        source: str,
+        *,
+        top: str | None = None,
+        defines: dict[str, str] | None = None,
+        include_paths: list[Path | str] | None = None,
+    ) -> AddrmapNode:
+        compiler = RDLCompiler()
+        # Use delete=False to keep the file around after closing
+        with NamedTemporaryFile("w", suffix=".rdl", dir=tmp_path, delete=False) as tmp_file:
+            tmp_file.write(source)
+            tmp_file.flush()
+
+            try:
+                compiler.compile_file(
+                    tmp_file.name,
+                    incl_search_paths=(list(map(str, include_paths)) if include_paths else None),
+                    defines=defines,
+                )
+                if top is not None:
+                    root = compiler.elaborate(top)  # type:ignore
+                    return root.top
+                root = compiler.elaborate()  # type:ignore
+                return root.top
+            except RDLCompileError:
+                # Print error messages if available
+                if hasattr(compiler, "print_messages"):
+                    compiler.print_messages()  # type:ignore
+                raise
+
+    return _compile