pytester: add method ``TmpTestdir.delete_loaded_modules()``

, and call it from ``inline_run()`` to allow temporary modules to be reloaded.

--HG--
branch : pytester-inline-run-clean-sys-modules

AUTHORS

@@ -48,3 +48,4 @@ Nicolas Delaby
 Tom Viner
 Dave Hunt
 Charles Cloud
+schettino72

CHANGELOG

@@ -1,6 +1,8 @@
 2.8.0.dev (compared to 2.7.X)
 -----------------------------
 
+- pytester: add method ``TmpTestdir.delete_loaded_modules()``, and call it
+  from ``inline_run()`` to allow temporary modules to be reloaded.
 
 2.7.1.dev (compared to 2.7.0)
 -----------------------------

_pytest/pytester.py

@@ -266,7 +266,7 @@ class TmpTestdir:
 
         Some methods modify the global interpreter state and this
         tries to clean this up.  It does not remove the temporary
-        directlry however so it can be looked at after the test run
+        directory however so it can be looked at after the test run
         has finished.
 
         """
@@ -274,7 +274,15 @@ class TmpTestdir:
             sys.path.remove(p)
         if hasattr(self, '_olddir'):
             self._olddir.chdir()
-        # delete modules that have been loaded from tmpdir
+        self.delete_loaded_modules()
+
+    def delete_loaded_modules(self):
+        """Delete modules that have been loaded from tmpdir.
+
+        This allows the interpreter to catch module changes in case
+        the module is re-imported.
+
+        """
         for name, mod in list(sys.modules.items()):
             if mod:
                 fn = getattr(mod, '__file__', None)
@@ -539,6 +547,7 @@ class TmpTestdir:
         assert len(rec) == 1
         reprec = rec[0]
         reprec.ret = ret
+        self.delete_loaded_modules()
         return reprec
 
     def parseconfig(self, *args):

testing/test_pytester.py

@@ -2,6 +2,8 @@ import pytest
 import os
 from _pytest.pytester import HookRecorder
 from _pytest.core import PluginManager
+from _pytest.main import EXIT_OK, EXIT_TESTSFAILED
+
 
 def test_make_hook_recorder(testdir):
     item = testdir.getitem("def test_func(): pass")
@@ -121,3 +123,12 @@ def test_inprocess_plugins(testdir):
     testdir.inprocess_run([], [plugin])
 
     assert plugin.configured
+
+def test_inline_run_clean_modules(testdir):
+    test_mod = testdir.makepyfile("def test_foo(): assert True")
+    result = testdir.inline_run(str(test_mod))
+    assert result.ret == EXIT_OK
+    # rewrite module, now test should fail if module was re-imported
+    test_mod.write("def test_foo(): assert False")
+    result2 = testdir.inline_run(str(test_mod))
+    assert result2.ret == EXIT_TESTSFAILED