feat: add cdr validation and normalization domain

tests/unit/test_validation.py

@@ -0,0 +1,71 @@
+import pytest
+
+from core.domain.errors import CDRProcessingError, FailureReason
+from core.domain.validation import parse_raw_cdr
+
+
+def valid_payload() -> dict:
+    return {
+        "raw_id": "raw-001",
+        "src_ip": "10.240.12.1",
+        "device_id": "310410998877665",
+        "caller_num": "0019875551234",
+        "svc": "4G_DATA",
+        "up_bytes": 1048576,
+        "down_bytes": 4194304,
+        "rat": 6,
+        "lac": "4021",
+        "ci": "8812",
+        "epoch_start": 1726070000,
+        "epoch_end": 1726070300,
+    }
+
+def test_missing_required_field() -> None:
+    payload = valid_payload()
+    del payload["caller_num"]
+
+    with pytest.raises(CDRProcessingError) as exc_info:
+        parse_raw_cdr(payload)
+
+    error = exc_info.value
+
+    assert error.reason == FailureReason.MISSING_REQUIRED_FIELD
+    assert error.failed_field == "caller_num"
+
+def test_invalid_rat() -> None:
+    payload = valid_payload()
+    payload["rat"] = 99
+
+    with pytest.raises(CDRProcessingError) as exc_info:
+        parse_raw_cdr(payload)
+
+    error = exc_info.value
+
+    assert error.reason == FailureReason.INVALID_RAT_VALUE
+    assert error.failed_field == "rat"
+
+def test_epoch_start_after_end_is_invalid() -> None:
+    payload = valid_payload()
+
+    payload["epoch_start"] = 200
+    payload["epoch_end"] = 100
+
+    with pytest.raises(CDRProcessingError) as exc_info:
+        parse_raw_cdr(payload)
+
+    error = exc_info.value
+
+    assert error.reason == FailureReason.INVALID_EPOCH
+
+def test_negative_uploaded_bytes_is_invalid() -> None:
+    payload = valid_payload()
+
+    payload["up_bytes"] = -1
+
+    with pytest.raises(CDRProcessingError) as exc_info:
+        parse_raw_cdr(payload)
+
+    error = exc_info.value
+
+    assert error.reason == FailureReason.NORMALIZATION_ERROR
+    assert error.failed_field == "up_bytes"