Added a test case for the saxutils.prepare_input_source setSystemId bug.
diff --git a/Lib/test/output/test_sax b/Lib/test/output/test_sax
index 062a456..de49c80 100644
--- a/Lib/test/output/test_sax
+++ b/Lib/test/output/test_sax
@@ -8,6 +8,7 @@
 Passed test_expat_attrs_wattr
 Passed test_expat_dtdhandler
 Passed test_expat_entityresolver
+Passed test_expat_file
 Passed test_expat_incomplete
 Passed test_expat_incremental
 Passed test_expat_incremental_reset
@@ -30,4 +31,4 @@
 Passed test_xmlgen_ignorable
 Passed test_xmlgen_ns
 Passed test_xmlgen_pi
-31 tests, 0 failures
+32 tests, 0 failures
diff --git a/Lib/test/test_sax.py b/Lib/test/test_sax.py
index 59e14c5..b4c840b 100644
--- a/Lib/test/test_sax.py
+++ b/Lib/test/test_sax.py
@@ -185,6 +185,18 @@
 #
 # ===========================================================================
 
+# ===== XMLReader support
+
+def test_expat_file():
+    parser = create_parser()
+    result = StringIO()
+    xmlgen = XMLGenerator(result)
+
+    parser.setContentHandler(xmlgen)
+    parser.parse(open(findfile("test.xml")))
+
+    return result.getvalue() == xml_test_out
+
 # ===== DTDHandler support
 
 class TestDTDHandler: