Add test files (unit and integration tests)

tests/unit/test_analyzer.py

@@ -1,8 +1,6 @@
 """Unit tests for log analyzer."""
 
-import pytest
-from loglens.analyzers.analyzer import LogAnalyzer, AnalysisResult
-from loglens.analyzers.patterns import PatternLibrary, ErrorPattern
+from loglens.analyzers.patterns import ErrorPattern, PatternLibrary
 from loglens.analyzers.severity import SeverityClassifier, SeverityLevel
 from loglens.parsers.base import LogFormat
 
@@ -63,9 +61,7 @@ class TestPatternLibrary:
         """Test adding custom pattern."""
         library = PatternLibrary()
         custom = ErrorPattern(
-            name="Custom Error",
-            pattern="UNIQUE_CUSTOM_PATTERN_12345",
-            severity="error"
+            name="Custom Error", pattern="UNIQUE_CUSTOM_PATTERN_12345", severity="error"
         )
         library.add_pattern(custom)