test + fix(fio): reset _fio_version state between parses

- Add failing test for state leakage between consecutive parses
- Reset self._fio_version = None at start of parse_runs()
- Prevent stale version from first parse leaking into second parse

Addresses review feedback on PR #50.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: Agent VM

src/chronicler/processors/fio_processor.py

@@ -191,6 +191,9 @@ def parse_runs(self, extracted_result: Dict[str, Any]) -> Dict[str, Any]:
                 ...
             }
         """
+        # Reset state to prevent leakage between parse calls
+        self._fio_version = None
+
         files = extracted_result.get("files") or {}
         if files.get("fio_results_json"):
             # Direct file path (demo / tmp/coremark-style layout)

tests/test_fio_version_extraction.py

@@ -205,3 +205,96 @@ def test_fio_version_no_wrapper_version(tmp_path):
     # Wrapper version should be "unknown" when test_info is missing
     assert test_info.wrapper_version == "unknown", \
         f"Expected wrapper_version='unknown', got '{test_info.wrapper_version}'"
+
+
+def test_fio_version_resets_between_parses(tmp_path):
+    """Processor reuse: version state should not leak between parse_runs() calls."""
+    # First parse: fio-results.json WITH benchmark version
+    fio_data_with_version = {
+        "fio version": "fio-3.36",
+        "timestamp": 1776775499,
+        "jobs": [
+            {
+                "jobname": "test-job-1",
+                "groupid": 0,
+                "elapsed": 120,
+                "read": {
+                    "io_bytes": 1000000,
+                    "bw": 8333,
+                    "iops": 2083,
+                    "runtime": 120000,
+                    "total_ios": 250000,
+                    "lat_ns": {"mean": 480000, "min": 100000, "max": 1000000},
+                    "clat_ns": {"mean": 470000, "min": 90000, "max": 990000},
+                    "slat_ns": {"mean": 10000, "min": 1000, "max": 50000}
+                }
+            }
+        ]
+    }
+
+    fio_json_path1 = tmp_path / "fio-results-1.json"
+    with open(fio_json_path1, "w") as f:
+        json.dump(fio_data_with_version, f)
+
+    # Create test_info file with wrapper version for fallback
+    test_info = {
+        "fio": {
+            "test_name": "fio",
+            "repo_file": "v2.1.tar.gz"
+        }
+    }
+    test_info_path = tmp_path / "test_info"
+    with open(test_info_path, "w") as f:
+        json.dump(test_info, f)
+
+    processor = FioProcessor(str(tmp_path))
+    extracted_result1 = {"files": {"fio_results_json": str(fio_json_path1)},
+                        "extracted_path": str(tmp_path)}
+
+    # First parse
+    with patch.object(processor.archive_handler, "extract_result_archive") as mock_extract:
+        mock_extract.return_value = extracted_result1
+        processor.parse_runs(extracted_result1)
+        test_info1 = processor.build_test_info()
+
+    assert test_info1.version == "fio-3.36", "First parse should extract benchmark version"
+
+    # Second parse: fio-results.json WITHOUT benchmark version (reusing same processor instance)
+    fio_data_without_version = {
+        "timestamp": 1776775500,
+        "jobs": [
+            {
+                "jobname": "test-job-2",
+                "groupid": 0,
+                "elapsed": 120,
+                "read": {
+                    "io_bytes": 2000000,
+                    "bw": 16666,
+                    "iops": 4166,
+                    "runtime": 120000,
+                    "total_ios": 500000,
+                    "lat_ns": {"mean": 240000, "min": 50000, "max": 500000},
+                    "clat_ns": {"mean": 235000, "min": 45000, "max": 495000},
+                    "slat_ns": {"mean": 5000, "min": 500, "max": 25000}
+                }
+            }
+        ]
+    }
+
+    fio_json_path2 = tmp_path / "fio-results-2.json"
+    with open(fio_json_path2, "w") as f:
+        json.dump(fio_data_without_version, f)
+
+    extracted_result2 = {"files": {"fio_results_json": str(fio_json_path2)},
+                        "extracted_path": str(tmp_path)}
+
+    # Second parse with same processor instance
+    with patch.object(processor.archive_handler, "extract_result_archive") as mock_extract:
+        mock_extract.return_value = extracted_result2
+        processor.parse_runs(extracted_result2)
+        test_info2 = processor.build_test_info()
+
+    # Should fall back to wrapper version, NOT retain stale "fio-3.36"
+    assert test_info2.version == "v2.1", \
+        f"Second parse should fall back to wrapper version, not retain stale 'fio-3.36'. Got '{test_info2.version}'"
+    assert test_info2.wrapper_version == "v2.1"