Modernize modulefinder module and tests a bit.

The tests don’t use an internal distutils function anymore, and use
regular assertEqual with sorted lists instead of a convoluted manual
diff.

Lib/modulefinder.py

 """Find modules used by a script, using introspection."""
 
-from __future__ import generators
 import dis
 import imp
 import marshal
@@ -9,8 +8,6 @@ import sys
 import types
 import struct
 
-READ_MODE = "rU"
-
 # XXX Clean up once str8's cstor matches bytes.
 LOAD_CONST = bytes([dis.opname.index('LOAD_CONST')])
 IMPORT_NAME = bytes([dis.opname.index('IMPORT_NAME')])
@@ -29,8 +26,7 @@ packagePathMap = {}
 
 # A Public interface
 def AddPackagePath(packagename, path):
-    paths = packagePathMap.get(packagename, [])
-    paths.append(path)
+    paths = packagePathMap.setdefault(packagename, []).append(path)
     packagePathMap[packagename] = paths
 
 replacePackageMap = {}
@@ -106,14 +102,14 @@ class ModuleFinder:
 
     def run_script(self, pathname):
         self.msg(2, "run_script", pathname)
-        with open(pathname, READ_MODE) as fp:
+        with open(pathname) as fp:
             stuff = ("", "r", imp.PY_SOURCE)
             self.load_module('__main__', fp, pathname, stuff)
 
     def load_file(self, pathname):
         dir, name = os.path.split(pathname)
         name, ext = os.path.splitext(name)
-        with open(pathname, READ_MODE) as fp:
+        with open(pathname) as fp:
             stuff = (ext, "r", imp.PY_SOURCE)
             self.load_module(name, fp, pathname, stuff)
 
@@ -270,7 +266,8 @@ class ModuleFinder:
         try:
             m = self.load_module(fqname, fp, pathname, stuff)
         finally:
-            if fp: fp.close()
+            if fp:
+                fp.close()
         if parent:
             setattr(parent, partname, m)
         self.msgout(3, "import_module ->", m)
@@ -662,4 +659,4 @@ if __name__ == '__main__':
     try:
         mf = test()
     except KeyboardInterrupt:
-        print("\n[interrupt]")
+        print("\n[interrupted]")

Lib/test/test_modulefinder.py

-import __future__
 import os
+import errno
+import shutil
 import unittest
-import distutils.dir_util
 import tempfile
 
 from test import support
@@ -9,7 +9,7 @@ from test import support
 import modulefinder
 
 TEST_DIR = tempfile.mkdtemp()
-TEST_PATH = [TEST_DIR, os.path.dirname(__future__.__file__)]
+TEST_PATH = [TEST_DIR, os.path.dirname(tempfile.__file__)]
 
 # Each test description is a list of 5 items:
 #
@@ -196,12 +196,17 @@ a/module.py
                                 from . import bar
 """]
 
+
 def open_file(path):
-    ##print "#", os.path.abspath(path)
     dirname = os.path.dirname(path)
-    distutils.dir_util.mkpath(dirname)
+    try:
+        os.makedirs(dirname)
+    except OSError as e:
+        if e.errno != errno.EEXIST:
+            raise
     return open(path, "w")
 
+
 def create_package(source):
     ofi = None
     try:
@@ -216,6 +221,7 @@ def create_package(source):
         if ofi:
             ofi.close()
 
+
 class ModuleFinderTest(unittest.TestCase):
     def _do_test(self, info, report=False):
         import_this, modules, missing, maybe_missing, source = info
@@ -234,19 +240,17 @@ class ModuleFinderTest(unittest.TestCase):
 ##                    import traceback; traceback.print_exc()
 ##                sys.path = opath
 ##                return
-            modules = set(modules)
-            found = set(mf.modules.keys())
-            more = list(found - modules)
-            less = list(modules - found)
+            modules = sorted(set(modules))
+            found = sorted(mf.modules)
             # check if we found what we expected, not more, not less
-            self.assertEqual((more, less), ([], []))
+            self.assertEqual(found, modules)
 
             # check for missing and maybe missing modules
             bad, maybe = mf.any_missing_maybe()
             self.assertEqual(bad, missing)
             self.assertEqual(maybe, maybe_missing)
         finally:
-            distutils.dir_util.remove_tree(TEST_DIR)
+            shutil.rmtree(TEST_DIR)
 
     def test_package(self):
         self._do_test(package_test)
@@ -254,25 +258,23 @@ class ModuleFinderTest(unittest.TestCase):
     def test_maybe(self):
         self._do_test(maybe_test)
 
-    if getattr(__future__, "absolute_import", None):
+    def test_maybe_new(self):
+        self._do_test(maybe_test_new)
 
-        def test_maybe_new(self):
-            self._do_test(maybe_test_new)
+    def test_absolute_imports(self):
+        self._do_test(absolute_import_test)
 
-        def test_absolute_imports(self):
-            self._do_test(absolute_import_test)
+    def test_relative_imports(self):
+        self._do_test(relative_import_test)
 
-        def test_relative_imports(self):
-            self._do_test(relative_import_test)
+    def test_relative_imports_2(self):
+        self._do_test(relative_import_test_2)
 
-        def test_relative_imports_2(self):
-            self._do_test(relative_import_test_2)
+    def test_relative_imports_3(self):
+        self._do_test(relative_import_test_3)
 
-        def test_relative_imports_3(self):
-            self._do_test(relative_import_test_3)
 
 def test_main():
-    distutils.log.set_threshold(distutils.log.WARN)
     support.run_unittest(ModuleFinderTest)
 
 if __name__ == "__main__":