Simplify metadata for invalid xml in output

Removes possibly non-free resource enron1.pdf.

debian/copyright

@@ -95,12 +95,6 @@ Files: tests/resources/vector.pdf
 Copyright: (C) 2018 Catscratch
 License: Expat
 
-Files: test/resources/enron*.pdf
-Copyright: EnronData.org
-License: CC-BY-3.0
- See: https://enrondata.readthedocs.io/en/latest/data/edo-enron-email-pst-dataset/
-Comment: Unprocessed.
-
 Files: src/ocrmypdf/data/sRGB.icc
 Copyright:  Kai-Uwe Behrmann <www.behrmann.name>
             Marti Maria <www.littlecms.com>

tests/test_metadata.py

@@ -313,19 +313,26 @@ def test_metadata_fixup_warning(resources, outdir, caplog):
 
 
 def test_prevent_gs_invalid_xml(resources, outdir):
-    from ocrmypdf.__main__ import parser
+    from ocrmypdf.cli import parser
     from ocrmypdf._pipeline import convert_to_pdfa
     from ocrmypdf.pdfa import generate_pdfa_ps
     from ocrmypdf.pdfinfo import PdfInfo
 
     generate_pdfa_ps(outdir / 'pdfa.ps')
-    copyfile(resources / 'enron1.pdf', outdir / 'layers.rendered.pdf')
+    copyfile(resources / 'trivial.pdf', outdir / 'layers.rendered.pdf')
+
+    # Inject a string with a trailing nul character into the DocumentInfo
+    # dictionary of this PDF, as often occurs in practice.
+    with pikepdf.open(outdir / 'layers.rendered.pdf') as pike:
+        pike.Root.DocumentInfo = pikepdf.Dictionary(
+            Title=b'String with trailing nul\x00'
+        )
 
     options = parser.parse_args(
         args=['-j', '1', '--output-type', 'pdfa-2', 'a.pdf', 'b.pdf']
     )
-    pdfinfo = PdfInfo(resources / 'enron1.pdf')
-    context = PDFContext(options, outdir, resources / 'enron1.pdf', pdfinfo)
+    pdfinfo = PdfInfo(outdir / 'layers.rendered.pdf')
+    context = PDFContext(options, outdir, outdir / 'layers.rendered.pdf', pdfinfo)
 
     convert_to_pdfa(
         str(outdir / 'layers.rendered.pdf'), str(outdir / 'pdfa.ps'), context
@@ -339,5 +346,6 @@ def test_prevent_gs_invalid_xml(resources, outdir):
             xmp_start = mm.find(XMP_MAGIC)
             xmp_end = mm.rfind(b'<?xpacket end', xmp_start)
             assert 0 < xmp_start < xmp_end
+            # Ensure we did not carry the nul forward.
             assert mm.find(b'&#0;', xmp_start, xmp_end) == -1, "found escaped nul"
             assert mm.find(b'\x00', xmp_start, xmp_end) == -1