Raise CollectError if import test module fails

One of the reasons for failing to import the test module is invalid Python
identifiers in the full package path of the test module.

fix #1426

CHANGELOG.rst

@@ -39,7 +39,9 @@
   parametrize.
   Thanks `@palaviv`_ for the complete PR (`#1474`_).
 
-*
+* Fix `#1426`_ Make ImportError during collection more explicit by reminding
+  the user to check the name of the test module/package(s).
+  Thanks `@omarkohl`_ for the complete PR (`#1520`_).
 
 .. _@milliams: https://github.com/milliams
 .. _@novas0x2a: https://github.com/novas0x2a
@@ -49,6 +51,7 @@
 .. _@palaviv: https://github.com/palaviv
 .. _@omarkohl: https://github.com/omarkohl
 
+.. _#1426: https://github.com/pytest-dev/pytest/issues/1426
 .. _#1428: https://github.com/pytest-dev/pytest/pull/1428
 .. _#1444: https://github.com/pytest-dev/pytest/pull/1444
 .. _#1441: https://github.com/pytest-dev/pytest/pull/1441
@@ -57,6 +60,7 @@
 .. _#1468: https://github.com/pytest-dev/pytest/pull/1468
 .. _#1474: https://github.com/pytest-dev/pytest/pull/1474
 .. _#1502: https://github.com/pytest-dev/pytest/pull/1502
+.. _#1520: https://github.com/pytest-dev/pytest/pull/1520
 .. _#372: https://github.com/pytest-dev/pytest/issues/372
 
 2.9.2.dev1

_pytest/python.py

@@ -636,6 +636,14 @@ class Module(pytest.File, PyCollector):
                 "unique basename for your test file modules"
                  % e.args
             )
+        except ImportError:
+            exc_class, exc, _ = sys.exc_info()
+            raise self.CollectError(
+                "ImportError while importing test module '%s'.\n"
+                "Original error message:\n'%s'\n"
+                "Make sure your test modules/packages have valid Python names."
+                % (self.fspath, exc or exc_class)
+            )
         #print "imported test module", mod
         self.config.pluginmanager.consider_module(mod)
         return mod

testing/acceptance_test.py

@@ -117,7 +117,8 @@ class TestGeneralUsage:
         result = testdir.runpytest(p)
         result.stdout.fnmatch_lines([
             #XXX on jython this fails:  ">   import import_fails",
-            "E   ImportError: No module named *does_not_work*",
+            "ImportError while importing test module*",
+            "'No module named *does_not_work*",
         ])
         assert result.ret == 1
 

testing/python/collect.py

@@ -5,14 +5,16 @@ from textwrap import dedent
 import _pytest._code
 import py
 import pytest
-from _pytest.main import EXIT_NOTESTSCOLLECTED
+from _pytest.main import (
+    Collector,
+    EXIT_NOTESTSCOLLECTED
+)
 
 
 class TestModule:
     def test_failing_import(self, testdir):
         modcol = testdir.getmodulecol("import alksdjalskdjalkjals")
-        pytest.raises(ImportError, modcol.collect)
+        pytest.raises(Collector.CollectError, modcol.collect)
-        pytest.raises(ImportError, modcol.collect)
 
     def test_import_duplicate(self, testdir):
         a = testdir.mkdir("a")
@@ -60,6 +62,16 @@ class TestModule:
         modcol = testdir.getmodulecol("pytest_plugins='xasdlkj',")
         pytest.raises(ImportError, lambda: modcol.obj)
 
+    def test_invalid_test_module_name(self, testdir):
+        a = testdir.mkdir('a')
+        a.ensure('test_one.part1.py')
+        result = testdir.runpytest("-rw")
+        result.stdout.fnmatch_lines([
+            "ImportError while importing test module*test_one.part1*",
+            "Make sure your test modules/packages have valid Python names.",
+        ])
+
+
 class TestClass:
     def test_class_with_init_warning(self, testdir):
         testdir.makepyfile("""

testing/test_collection.py

@@ -176,7 +176,8 @@ class TestPrunetraceback:
         assert "__import__" not in result.stdout.str(), "too long traceback"
         result.stdout.fnmatch_lines([
             "*ERROR collecting*",
-            "*mport*not_exists*"
+            "ImportError while importing test module*",
+            "'No module named *not_exists*",
         ])
 
     def test_custom_repr_failure(self, testdir):

testing/test_session.py

@@ -42,7 +42,7 @@ class SessionTests:
         reprec = testdir.inline_run(tfile)
         l = reprec.getfailedcollections()
         assert len(l) == 1
-        out = l[0].longrepr.reprcrash.message
+        out = str(l[0].longrepr)
         assert out.find('does_not_work') != -1
 
     def test_raises_output(self, testdir):

testing/test_terminal.py

@@ -276,8 +276,8 @@ class TestCollectonly:
         assert result.ret == 1
         result.stdout.fnmatch_lines(_pytest._code.Source("""
             *ERROR*
-            *import Errlk*
             *ImportError*
+            *No module named *Errlk*
             *1 error*
         """).strip())
 
@@ -665,8 +665,8 @@ class TestGenericReporting:
         testdir.makepyfile("import xyz\n")
         result = testdir.runpytest(*option.args)
         result.stdout.fnmatch_lines([
-            "?   import xyz",
+            "ImportError while importing*",
-            "E   ImportError: No module named *xyz*",
+            "'No module named *xyz*",
             "*1 error*",
         ])