Check for *Error instead of ImportError in tests

This tests originally checked for ImportError. Since Python 3.6
ModuleNotFoundError is raised in this context instead, the test didn't work
as it is text based (so exception inheritance does not save the day).

The test now simply checks for any *Error, which makes it less specific,
but still valuable.

Fixes pytest-dev#2132

testing/test_doctest.py

@@ -211,8 +211,8 @@ def test_doctest_unex_importerror_only_txt(self, testdir):
         # doctest is never executed because of error during hello.py collection
         result.stdout.fnmatch_lines([
             "*>>> import asdals*",
-            "*UNEXPECTED*ImportError*",
-            "ImportError: No module named *asdal*",
+            "*UNEXPECTED*Error*",
+            "*Error: No module named *asdal*",
         ])
 
     def test_doctest_unex_importerror_with_module(self, testdir):
@@ -227,7 +227,7 @@ def test_doctest_unex_importerror_with_module(self, testdir):
         # doctest is never executed because of error during hello.py collection
         result.stdout.fnmatch_lines([
             "*ERROR collecting hello.py*",
-            "*ImportError: No module named *asdals*",
+            "*Error: No module named *asdals*",
             "*Interrupted: 1 errors during collection*",
         ])