feat: collector tracer bullet (#21)\n\nSmartctl acquisition with validation\nSysfs controller identity acquisition\nIdentity normalization (strip, no case fold, blank handling)\nSQLite store in WAL mode with six entities\nSchema versioning via PRAGMA user_version\nInvariant validation (negative bytes, etc.)\n17 passing tests across two test files\n\nCloses #21

tests/test_identity_normalization.py

@@ -0,0 +1,96 @@
+"""Test identity normalization per specification.
+
+From spec §2.3:
+- strip trailing spaces and newlines
+- no case folding
+- empty-after-strip stored blank
+
+Padded and unpadded renderings of the same field yield byte-identical stored values.
+"""
+import pytest
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.collector import normalize_identity
+
+
+def test_strip_trailing_spaces():
+    """Trailing spaces are stripped."""
+    identity = {"subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678  "}
+    result = normalize_identity(identity)
+    assert result == "nqn.2014-08.org.nvmexpress:uuid:12345678"
+
+
+def test_strip_trailing_newlines():
+    """Trailing newlines are stripped."""
+    identity = {"subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678\n"}
+    result = normalize_identity(identity)
+    assert result == "nqn.2014-08.org.nvmexpress:uuid:12345678"
+
+
+def test_strip_trailing_spaces_and_newlines():
+    """Trailing spaces and newlines are stripped."""
+    identity = {"subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678  \n\n"}
+    result = normalize_identity(identity)
+    assert result == "nqn.2014-08.org.nvmexpress:uuid:12345678"
+
+
+def test_no_case_folding():
+    """Case is preserved - no case folding."""
+    identity = {"subnqn": "NQN.2014-08.ORG.NVMEXPRESS:UUID:12345678"}
+    result = normalize_identity(identity)
+    assert result == "NQN.2014-08.ORG.NVMEXPRESS:UUID:12345678"
+
+
+def test_empty_after_strip_stored_blank():
+    """Empty after strip is stored as blank string."""
+    identity = {"subnqn": "   \n\n  "}
+    result = normalize_identity(identity)
+    assert result == ""
+
+
+def test_fallback_to_model_serial():
+    """When subnqn is empty, falls back to model|serial."""
+    identity = {
+        "subnqn": "",
+        "mn": "Samsung SSD 970 EVO Plus 1TB",
+        "sn": "S4EWNX0N123456",
+    }
+    result = normalize_identity(identity)
+    assert result == "Samsung SSD 970 EVO Plus 1TB|S4EWNX0N123456"
+
+
+def test_fallback_model_serial_normalized():
+    """Model and serial are also normalized."""
+    identity = {
+        "subnqn": "",
+        "mn": "Samsung SSD 970 EVO Plus 1TB\n",
+        "sn": "S4EWNX0N123456  ",
+    }
+    result = normalize_identity(identity)
+    assert result == "Samsung SSD 970 EVO Plus 1TB|S4EWNX0N123456"
+
+
+def test_all_keys_blank_returns_blank():
+    """When all keys are blank, returns blank (degraded identity)."""
+    identity = {
+        "subnqn": "",
+        "mn": "",
+        "sn": "",
+    }
+    result = normalize_identity(identity)
+    assert result == ""
+
+
+def test_byte_identical_for_padded_unpadded():
+    """Padded and unpadded renderings yield byte-identical values."""
+    padded = {"subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678  \n"}
+    unpadded = {"subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678"}
+    
+    result_padded = normalize_identity(padded)
+    result_unpadded = normalize_identity(unpadded)
+    
+    assert result_padded == result_unpadded
+    assert result_padded == "nqn.2014-08.org.nvmexpress:uuid:12345678"