diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index e98952ff18..ca64bfa29a 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -275,11 +275,11 @@ jobs:
         run: target/release/rustpython -m test -j 1 -u all --slowest --fail-env-changed -v -x ${{ env.PLATFORM_INDEPENDENT_TESTS }}
       - if: runner.os == 'macOS'
         name: run cpython platform-dependent tests (MacOS)
-        run: target/release/rustpython -m test -j 1 all --slowest --fail-env-changed -v -x ${{ env.PLATFORM_INDEPENDENT_TESTS }} ${{ env.MACOS_SKIPS }}
+        run: target/release/rustpython -m test -j 1 --slowest --fail-env-changed -v -x ${{ env.PLATFORM_INDEPENDENT_TESTS }} ${{ env.MACOS_SKIPS }}
       - if: runner.os == 'Windows'
         name: run cpython platform-dependent tests (windows partial - fixme)
         run:
-          target/release/rustpython -m test -j 1 all --slowest --fail-env-changed -v -x ${{ env.PLATFORM_INDEPENDENT_TESTS }} ${{ env.WINDOWS_SKIPS }}
+          target/release/rustpython -m test -j 1 --slowest --fail-env-changed -v -x ${{ env.PLATFORM_INDEPENDENT_TESTS }} ${{ env.WINDOWS_SKIPS }}
       - if: runner.os != 'Windows'
         name: check that --install-pip succeeds
         run: |
diff --git a/Lib/filecmp.py b/Lib/filecmp.py
index 950b2afd4c..30bd900fa8 100644
--- a/Lib/filecmp.py
+++ b/Lib/filecmp.py
@@ -10,10 +10,7 @@
 
 """
 
-try:
-    import os
-except ImportError:
-    import _dummy_os as os
+import os
 import stat
 from itertools import filterfalse
 from types import GenericAlias
@@ -160,17 +157,17 @@ def phase2(self): # Distinguish files, directories, funnies
             a_path = os.path.join(self.left, x)
             b_path = os.path.join(self.right, x)
 
-            ok = 1
+            ok = True
             try:
                 a_stat = os.stat(a_path)
             except OSError:
                 # print('Can\'t stat', a_path, ':', why.args[1])
-                ok = 0
+                ok = False
             try:
                 b_stat = os.stat(b_path)
             except OSError:
                 # print('Can\'t stat', b_path, ':', why.args[1])
-                ok = 0
+                ok = False
 
             if ok:
                 a_type = stat.S_IFMT(a_stat.st_mode)
@@ -245,7 +242,7 @@ def report_full_closure(self): # Report on self and subdirs recursively
 
     methodmap = dict(subdirs=phase4,
                      same_files=phase3, diff_files=phase3, funny_files=phase3,
-                     common_dirs = phase2, common_files=phase2, common_funny=phase2,
+                     common_dirs=phase2, common_files=phase2, common_funny=phase2,
                      common=phase1, left_only=phase1, right_only=phase1,
                      left_list=phase0, right_list=phase0)
 
diff --git a/Lib/genericpath.py b/Lib/genericpath.py
index b767a32981..1bd5b3897c 100644
--- a/Lib/genericpath.py
+++ b/Lib/genericpath.py
@@ -3,10 +3,7 @@
 Do not use directly.  The OS specific modules import the appropriate
 functions from this module themselves.
 """
-try:
-    import os
-except ImportError:
-    import _dummy_os as os
+import os
 import stat
 
 __all__ = ['commonprefix', 'exists', 'getatime', 'getctime', 'getmtime',