test: add export pdf functionality tests

tests/test_pdf_export.py

@@ -0,0 +1,20 @@
+"""Test PDF export from the UI exports module."""
+
+from code_tribunal.ui.exports import export_pdf
+
+
+def test_export_pdf_generates_file():
+    """export_pdf should produce a non-empty PDF file from a context dict."""
+    ctx = {
+        "evidence": "## Evidence\n\n- Finding 1: hardcoded password in config.py:42",
+        "verdict": "## Verdict\n\nOverall: GUILTY\nRisk Score: 78/100",
+        "report": "## Final Report\n\nExecutive Summary: Code contains critical security vulnerabilities.",
+    }
+
+    pdf_path = export_pdf(ctx)
+
+    from pathlib import Path
+    assert Path(pdf_path).exists(), f"PDF not created at {pdf_path}"
+    size = Path(pdf_path).stat().st_size
+    assert size > 500, f"PDF is too small ({size} bytes), likely broken"
+    print(f"\nPDF generated: {pdf_path} ({size:,} bytes)")