Display traceback from Import errors using pytest's short representation

Also omit pytest's own modules and internal libraries (py and pluggy) in low verbosity

Fix #1976

testing/python/collect.py

@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+import os
 import sys
 from textwrap import dedent
 
@@ -71,8 +72,12 @@ class TestModule:
             "Hint: make sure your test modules/packages have valid Python names.",
         ])
 
-    def test_show_full_traceback_import_error(self, testdir):
-        """Import errors when collecting modules should display the full traceback (#1976)."""
+    @pytest.mark.parametrize('verbose', [0, 1, 2])
+    def test_show_traceback_import_error(self, testdir, verbose):
+        """Import errors when collecting modules should display the traceback (#1976).
+
+        With low verbosity we omit pytest and internal modules, otherwise show all traceback entries.
+        """
         testdir.makepyfile(
             foo_traceback_import_error="""
                from bar_traceback_import_error import NOT_AVAILABLE
@@ -82,15 +87,23 @@ class TestModule:
         testdir.makepyfile("""
                import foo_traceback_import_error
         """)
-        result = testdir.runpytest()
+        args = ('-v',) * verbose
+        result = testdir.runpytest(*args)
         result.stdout.fnmatch_lines([
             "ImportError while importing test module*",
-            "Original traceback:",
+            "Traceback:",
             "*from bar_traceback_import_error import NOT_AVAILABLE",
             "*cannot import name *NOT_AVAILABLE*",
         ])
         assert result.ret == 2
 
+        stdout = result.stdout.str()
+        for name in ('_pytest', os.path.join('py', '_path')):
+            if verbose == 2:
+                assert name in stdout
+            else:
+                assert name not in stdout
+
 
 class TestClass:
     def test_class_with_init_warning(self, testdir):