change test module importing behaviour to append to sys.path

instead of prepending.  This better allows to run test modules
against installated versions of a package even if the package
under test has the same import root.  In this example::

   testing/__init__.py
   testing/test_pkg_under_test.py
   pkg_under_test/

the tests will preferrably run against the installed version
of pkg_under_test whereas before they would always pick
up the local version.

--HG--
branch : prefer_installed

CHANGELOG

@@ -1,6 +1,19 @@
 2.8.0.dev (compared to 2.7.X)
 -----------------------------
 
+- change test module importing behaviour to append to sys.path
+  instead of prepending.  This better allows to run test modules
+  against installated versions of a package even if the package
+  under test has the same import root.  In this example::
+
+        testing/__init__.py
+        testing/test_pkg_under_test.py
+        pkg_under_test/ 
+
+  the tests will preferrably run against the installed version 
+  of pkg_under_test whereas before they would always pick 
+  up the local version.  Thanks Holger Krekel.
+
 
 2.7.1.dev (compared to 2.7.0)
 -----------------------------

_pytest/__init__.py

@@ -1,2 +1,2 @@
 #
-__version__ = '2.8.0.dev1'
+__version__ = '2.8.0.dev2'

_pytest/pytester.py

@@ -254,7 +254,7 @@ class TmpTestdir:
             break
         self.tmpdir = tmpdir
         self.plugins = []
-        self._syspathremove = []
+        self._savesyspath = list(sys.path)
         self.chdir() # always chdir
         self.request.addfinalizer(self.finalize)
 
@@ -270,8 +270,7 @@ class TmpTestdir:
         has finished.
 
         """
-        for p in self._syspathremove:
+        sys.path[:] = self._savesyspath
-            sys.path.remove(p)
         if hasattr(self, '_olddir'):
             self._olddir.chdir()
         # delete modules that have been loaded from tmpdir
@@ -370,7 +369,6 @@ class TmpTestdir:
         if path is None:
             path = self.tmpdir
         sys.path.insert(0, str(path))
-        self._syspathremove.append(str(path))
 
     def mkdir(self, name):
         """Create a new (sub)directory."""

_pytest/python.py

@@ -485,7 +485,7 @@ class Module(pytest.File, PyCollector):
     def _importtestmodule(self):
         # we assume we are only called once per module
         try:
-            mod = self.fspath.pyimport(ensuresyspath=True)
+            mod = self.fspath.pyimport(ensuresyspath="append")
         except SyntaxError:
             raise self.CollectError(
                 py.code.ExceptionInfo().getrepr(style="short"))
@@ -2057,3 +2057,4 @@ def get_scope_node(node, scope):
             return node.session
         raise ValueError("unknown scope")
     return node.getparent(cls)
+

setup.py

@@ -31,12 +31,12 @@ def get_version():
 def has_environment_marker_support():
     """
     Tests that setuptools has support for PEP-426 environment marker support.
-    
+
-    The first known release to support it is 0.7 (and the earliest on PyPI seems to be 0.7.2 
+    The first known release to support it is 0.7 (and the earliest on PyPI seems to be 0.7.2
     so we're using that), see: http://pythonhosted.org/setuptools/history.html#id142
-    
+
     References:
-    
+
     * https://wheel.readthedocs.org/en/latest/index.html#defining-conditional-dependencies
     * https://www.python.org/dev/peps/pep-0426/#environment-markers
     """
@@ -48,7 +48,7 @@ def has_environment_marker_support():
 
 
 def main():
-    install_requires = ['py>=1.4.25']
+    install_requires = ['py>=1.4.27.dev2']
     extras_require = {}
     if has_environment_marker_support():
         extras_require[':python_version=="2.6" or python_version=="3.0" or python_version=="3.1"'] = ['argparse']

testing/python/collect.py

@@ -1,3 +1,5 @@
+import sys
+from textwrap import dedent
 import pytest, py
 
 class TestModule:
@@ -23,6 +25,24 @@ class TestModule:
             "*HINT*",
         ])
 
+    def test_import_appends_for_import(self, testdir, monkeypatch):
+        syspath = list(sys.path)
+        monkeypatch.setattr(sys, "path", syspath)
+        root1 = testdir.mkdir("root1")
+        root2 = testdir.mkdir("root2")
+        root1.ensure("x456.py")
+        root2.ensure("x456.py")
+        p = root2.join("test_x456.py")
+        p.write(dedent("""\
+            import x456
+            def test():
+                assert x456.__file__.startswith(%r)
+        """ % str(root1)))
+        syspath.insert(0, str(root1))
+        with root2.as_cwd():
+            reprec = testdir.inline_run()
+        reprec.assertoutcome(passed=1)
+
     def test_syntax_error_in_module(self, testdir):
         modcol = testdir.getmodulecol("this is a syntax error")
         pytest.raises(modcol.CollectError, modcol.collect)

testing/python/integration.py

@@ -238,7 +238,7 @@ def test_pytestconfig_is_session_scoped():
 
 
 class TestNoselikeTestAttribute:
-    def test_module(self, testdir):
+    def test_module_with_global_test(self, testdir):
         testdir.makepyfile("""
             __test__ = False
             def test_hello():
@@ -248,7 +248,7 @@ class TestNoselikeTestAttribute:
         assert not reprec.getfailedcollections()
         calls = reprec.getreports("pytest_runtest_logreport")
         assert not calls
-        
+
     def test_class_and_method(self, testdir):
         testdir.makepyfile("""
             __test__ = True

testing/test_core.py

@@ -772,6 +772,7 @@ def test_default_markers(testdir):
     ])
 
 def test_importplugin_issue375(testdir):
+    testdir.syspathinsert(testdir.tmpdir)
     testdir.makepyfile(qwe="import aaaa")
     excinfo = pytest.raises(ImportError, lambda: importplugin("qwe"))
     assert "qwe" not in str(excinfo.value)