resolves issue #59

resolves issue #48

Have the path.pyimport() helper raise an EnvironmentError if an
import of a given file returns a module that does not appear to
be coming from the actual path.  E.g. for a directory layout like this:

    a / test_whatever.py
    b / test_whatever.py

calling py.path.local("b/test_whatever.py").pyimport() will
fail if the other globally scoped test_whatever module was
loaded already.

--HG--
branch : trunk

_py/path/local.py

@@ -516,7 +516,16 @@ class LocalPath(FSBase):
                     self._prependsyspath(self.dirpath())
                 modname = self.purebasename
             mod = __import__(modname, None, None, ['__doc__'])
-            #self._module = mod
+            modfile = mod.__file__
+            if modfile[-4:] in ('.pyc', '.pyo'):
+                modfile = modfile[:-1]
+            elif modfile.endswith('$py.class'):
+                modfile = modfile[:-9] + '.py'
+            if not self.samefile(modfile):
+                raise EnvironmentError("mismatch:\n"
+                "imported module %r\n"
+                "does not stem from %r\n" 
+                "maybe __init__.py files are missing?" % (mod, str(self)))
             return mod
         else:
             try:

_py/test/plugin/pytest_pytester.py

@@ -70,6 +70,12 @@ class TmpTestdir:
             py.std.sys.path.remove(p)
         if hasattr(self, '_olddir'):
             self._olddir.chdir()
+        # delete modules that have been loaded from tmpdir
+        for name, mod in list(sys.modules.items()):
+            if mod:
+                fn = getattr(mod, '__file__', None)
+                if fn and fn.startswith(str(self.tmpdir)):
+                    del sys.modules[name]
 
     def getreportrecorder(self, obj):
         if isinstance(obj, py._com.Registry):

doc/changelog.txt

@@ -1,6 +1,11 @@
 Changes between 1.0.2 and '1.1.0b1'
 =====================================
 
+* fix issue48 and issue59: raise an Error if the module
+  from an imported test file does not seem to come from 
+  the filepath - avoids "same-name" confusion that has
+  been reported repeatedly
+
 * merged Ronny's nose-compatibility hacks: now
   nose-style setup_module() and setup() functions are 
   supported

testing/path/test_local.py

@@ -336,6 +336,27 @@ class TestImport:
         from xxxpackage import module1 
         assert module1 is mod1
 
+    def test_pyimport_check_filepath_consistency(self, monkeypatch, tmpdir):
+        name = 'pointsback123'
+        ModuleType = type(py.std.sys)
+        p = tmpdir.ensure(name + '.py')
+        for ending in ('.pyc', '$py.class', '.pyo'):
+            mod = ModuleType(name)
+            pseudopath = tmpdir.ensure(name+ending)
+            mod.__file__ = str(pseudopath)
+            monkeypatch.setitem(sys.modules, name, mod)
+            newmod = p.pyimport()
+            assert mod == newmod
+        monkeypatch.undo()
+        mod = ModuleType(name)
+        pseudopath = tmpdir.ensure(name+"123.py")
+        mod.__file__ = str(pseudopath)
+        monkeypatch.setitem(sys.modules, name, mod)
+        excinfo = py.test.raises(EnvironmentError, "p.pyimport()")
+        s = str(excinfo.value)
+        assert "mismatch" in s 
+        assert name+"123" in s 
+
 def test_pypkgdir(tmpdir):
     pkg = tmpdir.ensure('pkg1', dir=1)
     pkg.ensure("__init__.py")

testing/pytest/test_pycollect.py

@@ -16,6 +16,18 @@ class TestModule:
         py.test.raises(ImportError, modcol.collect)
         py.test.raises(ImportError, modcol.run)
 
+    def test_import_duplicate(self, testdir):
+        a = testdir.mkdir("a")
+        b = testdir.mkdir("b")
+        p = a.ensure("test_whatever.py")
+        p.pyimport()
+        del py.std.sys.modules['test_whatever']
+        b.ensure("test_whatever.py")
+        result = testdir.runpytest()
+        s = result.stdout.str()
+        assert 'mismatch' in s
+        assert 'test_whatever' in s
+
     def test_syntax_error_in_module(self, testdir):
         modcol = testdir.getmodulecol("this is a syntax error") 
         py.test.raises(SyntaxError, modcol.collect)