test: add unit tests for Postfix log parser (issue #18)

tests/test_parser.py

@@ -0,0 +1,113 @@
+import pytest
+from lib.maillogsentinel import log_utils
+
+class DummyLogger:
+    def warning(self, msg):
+        pass
+    def error(self, msg, *args, **kwargs):
+        pass
+    def info(self, msg):
+        pass
+    def debug(self, msg):
+        pass
+
+def dummy_reverse_lookup(ip, logger):
+    return ("dummyhost.example.com", None)
+
+class DummyIPInfoMgr:
+    def lookup_ip_info(self, ip):
+        return {"country_code": "US", "asn": "AS12345", "aso": "ExampleOrg"}
+
+def test_postfix_parser_happy_path():
+    """Test parsing a valid Postfix log line with SASL authentication (happy path)"""
+    log_line = "Oct  2 12:34:56 mail postfix/smtpd[12345]: 0123456789AB: client=example.com[192.0.2.1], sasl_method=PLAIN, sasl_username=user@example.com"
+    result = log_utils._parse_log_line(
+        log_line,
+        2025,
+        DummyLogger(),
+        DummyIPInfoMgr(),
+        dummy_reverse_lookup,
+    )
+    assert result is not None, "Parser should return a result for a valid log line"
+    assert result.get('date_s').endswith('12:34'), f"Unexpected date_s: {result.get('date_s')}"
+    assert result.get('ip') == '192.0.2.1'
+    assert result.get('user') == 'user@example.com'
+    assert result.get('server') == 'mail'
+    assert result.get('hostn') == 'dummyhost.example.com'
+    assert result.get('country_code') == 'US'
+    assert result.get('asn') == 'AS12345'
+    assert result.get('aso') == 'ExampleOrg'
+
+def test_postfix_parser_sasl_auth_failure():
+    """Test parsing a SASL authentication failure log line"""
+    log_line = "Oct  2 12:35:00 mail postfix/smtpd[12345]: warning: unknown[203.0.113.5]: SASL PLAIN authentication failed: authentication failure, sasl_username=baduser@example.com"
+    result = log_utils._parse_log_line(
+        log_line,
+        2025,
+        DummyLogger(),
+        DummyIPInfoMgr(),
+        dummy_reverse_lookup,
+    )
+    assert result is not None, "Parser should return a result for SASL auth failure log line"
+    assert result.get('ip') == '203.0.113.5'
+    assert result.get('user') == 'baduser@example.com'
+    assert result.get('server') == 'mail'
+
+def test_postfix_parser_garbled_line():
+    """Test parsing a garbled/unexpected log line that doesn't match expected format"""
+    log_line = "GARBLED LOG DATA WITHOUT EXPECTED FORMAT"
+    try:
+        result = log_utils._parse_log_line(
+            log_line,
+            2025,
+            DummyLogger(),
+            DummyIPInfoMgr(),
+            dummy_reverse_lookup,
+        )
+        # Should return None for unmatched lines, not raise exception
+        assert result is None, f"Expected None for garbled input, got: {result}"
+    except Exception as e:
+        pytest.fail(f"Parser raised an exception on garbled input: {e}")
+
+def test_postfix_parser_no_sasl_username():
+    """Test parsing a log line that matches the log format but has no sasl_username"""
+    log_line = "Oct  2 12:34:56 mail postfix/smtpd[12345]: 0123456789AB: client=example.com[192.0.2.1], sasl_method=PLAIN"
+    result = log_utils._parse_log_line(
+        log_line,
+        2025,
+        DummyLogger(),
+        DummyIPInfoMgr(),
+        dummy_reverse_lookup,
+    )
+    # Should return None because PAT regex won't match without sasl_username
+    assert result is None, f"Expected None for log line without sasl_username, got: {result}"
+
+def test_postfix_parser_invalid_date():
+    """Test parsing a log line with invalid date format"""
+    log_line = "XYZ 32 25:99:99 mail postfix/smtpd[12345]: client=example.com[192.0.2.1], sasl_username=user@example.com"
+    result = log_utils._parse_log_line(
+        log_line,
+        2025,
+        DummyLogger(),
+        DummyIPInfoMgr(),
+        dummy_reverse_lookup,
+    )
+    # Should return None due to invalid month or day
+    assert result is None, f"Expected None for invalid date format, got: {result}"
+
+def test_postfix_parser_reverse_dns_failure():
+    """Test parsing when reverse DNS lookup fails"""
+    def failing_reverse_lookup(ip, logger):
+        return (None, "DNS lookup failed")
+
+    log_line = "Oct  2 12:34:56 mail postfix/smtpd[12345]: client=example.com[192.0.2.1], sasl_username=user@example.com"
+    result = log_utils._parse_log_line(
+        log_line,
+        2025,
+        DummyLogger(),
+        DummyIPInfoMgr(),
+        failing_reverse_lookup,
+    )
+    assert result is not None
+    assert result.get('hostn') == 'null'
+    assert result.get('reverse_dns_status') == 'DNS lookup failed'