Tests: Add automated testing framework with coverage support

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/framework/bpf_test_case.py

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+from dataclasses import dataclass
+from pathlib import Path
+
+
+@dataclass
+class BpfTestCase:
+    path: Path
+    rel_path: str
+    is_expected_fail: bool = False
+    xfail_reason: str = ""
+    xfail_level: str = "ir"  # "ir" or "llc"
+    needs_vmlinux: bool = False
+    skip_reason: str = ""
+
+    @property
+    def test_id(self) -> str:
+        return self.rel_path.replace("/", "::")

tests/framework/collector.py

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+import sys
+from pathlib import Path
+
+if sys.version_info >= (3, 11):
+    import tomllib
+else:
+    import tomli as tomllib
+
+from .bpf_test_case import BpfTestCase
+
+TESTS_DIR = Path(__file__).parent.parent
+CONFIG_FILE = TESTS_DIR / "test_config.toml"
+
+VMLINUX_TEST_DIRS = {"passing_tests/vmlinux"}
+VMLINUX_TEST_PREFIXES = {
+    "failing_tests/vmlinux",
+    "failing_tests/xdp",
+}
+
+
+def _is_vmlinux_test(rel_path: str) -> bool:
+    for prefix in VMLINUX_TEST_DIRS | VMLINUX_TEST_PREFIXES:
+        if rel_path.startswith(prefix):
+            return True
+    return False
+
+
+def _load_config() -> dict:
+    if not CONFIG_FILE.exists():
+        return {}
+    with open(CONFIG_FILE, "rb") as f:
+        return tomllib.load(f)
+
+
+def collect_all_test_files() -> list[BpfTestCase]:
+    config = _load_config()
+    xfail_map: dict = config.get("xfail", {})
+
+    cases = []
+    for subdir in ("passing_tests", "failing_tests"):
+        for py_file in sorted((TESTS_DIR / subdir).rglob("*.py")):
+            rel = str(py_file.relative_to(TESTS_DIR))
+            needs_vmlinux = _is_vmlinux_test(rel)
+
+            xfail_entry = xfail_map.get(rel)
+            is_expected_fail = xfail_entry is not None
+            xfail_reason = xfail_entry.get("reason", "") if xfail_entry else ""
+            xfail_level = xfail_entry.get("level", "ir") if xfail_entry else "ir"
+
+            cases.append(
+                BpfTestCase(
+                    path=py_file,
+                    rel_path=rel,
+                    is_expected_fail=is_expected_fail,
+                    xfail_reason=xfail_reason,
+                    xfail_level=xfail_level,
+                    needs_vmlinux=needs_vmlinux,
+                )
+            )
+    return cases

tests/framework/compiler.py

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+import logging
+from pathlib import Path
+
+from pythonbpf.codegen import compile_to_ir, _run_llc
+
+
+def run_ir_generation(test_path: Path, output_ll: Path):
+    """Run compile_to_ir on a BPF test file.
+
+    Returns the (output, structs_sym_tab, maps_sym_tab) tuple from compile_to_ir.
+    Raises on exception. Any logging.ERROR records captured by pytest caplog
+    indicate a compile failure even when no exception is raised.
+    """
+    return compile_to_ir(str(test_path), str(output_ll), loglevel=logging.WARNING)
+
+
+def run_llc(ll_path: Path, obj_path: Path) -> bool:
+    """Compile a .ll file to a BPF .o using llc.
+
+    Raises subprocess.CalledProcessError on failure (llc uses check=True).
+    Returns True on success.
+    """
+    return _run_llc(str(ll_path), str(obj_path))

tests/framework/verifier.py

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+import subprocess
+import uuid
+from pathlib import Path
+
+
+def verify_object(obj_path: Path) -> tuple[bool, str]:
+    """Run bpftool prog load -d to verify a BPF object file against the kernel verifier.
+
+    Pins the program temporarily at /sys/fs/bpf/bpf_prog_test_<uuid>, then removes it.
+    Returns (success, combined_output). Requires sudo / root.
+    """
+    pin_path = f"/sys/fs/bpf/bpf_prog_test_{uuid.uuid4().hex[:8]}"
+    try:
+        result = subprocess.run(
+            ["sudo", "bpftool", "prog", "load", "-d", str(obj_path), pin_path],
+            capture_output=True,
+            text=True,
+            timeout=30,
+        )
+        output = result.stdout + result.stderr
+        return result.returncode == 0, output
+    except subprocess.TimeoutExpired:
+        return False, "bpftool timed out after 30s"
+    finally:
+        subprocess.run(["sudo", "rm", "-f", pin_path], check=False, capture_output=True)