tests: eliminate unnecessary mmap

tests/test_metadata.py

@@ -6,7 +6,6 @@
 
 
 import datetime
-import mmap
 from datetime import timezone
 from os import fspath
 from shutil import copyfile
@@ -356,17 +355,16 @@ def test_prevent_gs_invalid_xml(resources, outdir):
         str(outdir / 'layers.rendered.pdf'), str(outdir / 'pdfa.ps'), context
     )
 
-    with open(outdir / 'pdfa.pdf', 'r+b') as f:
-        with mmap.mmap(f.fileno(), 0) as mm:
-            # Since the XML may be invalid, we scan instead of actually feeding it
-            # to a parser.
-            XMP_MAGIC = b'W5M0MpCehiHzreSzNTczkc9d'
-            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
+    contents = (outdir / 'pdfa.pdf').read_bytes()
+    # Since the XML may be invalid, we scan instead of actually feeding it
+    # to a parser.
+    XMP_MAGIC = b'W5M0MpCehiHzreSzNTczkc9d'
+    xmp_start = contents.find(XMP_MAGIC)
+    xmp_end = contents.rfind(b'<?xpacket end', xmp_start)
+    assert 0 < xmp_start < xmp_end
+    # Ensure we did not carry the nul forward.
+    assert contents.find(b'&#0;', xmp_start, xmp_end) == -1, "found escaped nul"
+    assert contents.find(b'\x00', xmp_start, xmp_end) == -1
 
 
 def test_malformed_docinfo(caplog, resources, outdir):