add unit tests for local pdf exporter

tests/test_cli_pdf.py

@@ -0,0 +1,48 @@
+import pytest
+from pathlib import Path
+from securelens.scanners import LocalScanResult, VulnerabilityFinding
+from securelens.output.exporters import save_pdf
+
+@pytest.fixture(autouse=True)
+def setup_db():
+    # Override the database autouse fixture because these tests do not touch the DB.
+    pass
+
+def test_export_code_pdf_compiles(tmp_path):
+    # Setup mock result
+    findings = [
+        VulnerabilityFinding(
+            file_path="app.py",
+            severity="Critical",
+            issue="Hardcoded Secret Key",
+            explanation="Exposing secret key inside app.py.",
+            suggested_fix="Load key from environment",
+            line_number=5
+        ),
+        VulnerabilityFinding(
+            file_path="db.py",
+            severity="High",
+            issue="Raw SQL Statement",
+            explanation="SQL injection inside db.py.",
+            suggested_fix="Use parameterized queries",
+            line_number=20
+        )
+    ]
+    
+    result = LocalScanResult(
+        target="/home/user/project",
+        total_files_found=10,
+        files_triaged=["app.py", "db.py"],
+        vulnerabilities=findings,
+        ai_summary="This is a dummy AI report summary describing security posture."
+    )
+    result.compute_score()
+    
+    # Save to temp PDF file
+    out_file = tmp_path / "report.pdf"
+    
+    from securelens.output.pdf import export_code_pdf
+    export_code_pdf(result, str(out_file))
+    
+    assert out_file.exists()
+    assert out_file.stat().st_size > 1000  # should be non-empty PDF file