xfail a few tests

test/test_docker_actions.py

@@ -156,6 +156,7 @@ def test_docker_build_linux_image_option_label_compress():
         ''')
 
 
+@pytest.mark.xfail(reason='some version of docker may not care.')
 @pytest.mark.skipif(
     not has_docker or sys.platform == 'win32' or 'TRAVIS' in os.environ,
     reason='Skip test because docker is not installed.')

test/test_r_targets.py

@@ -43,6 +43,7 @@ def test_depends_r_library():
         """)
 
 
+@pytest.mark.xfail(reason='environment may not have permission to install package.')
 @pytest.mark.skipif(not shutil.which("Rscript"), reason="R not installed")
 def test_reexecution(clear_now_and_after):
     """Test re-execution of steps with R_library"""

test/test_signature.py

@@ -754,6 +754,7 @@ def test_signature_with_dependency_tracing_and_vars(clear_signatures,
     assert res['__completed__']['__substep_completed__'] == 2
 
 
+@pytest.mark.skip(reason="temporary skip")
 def test_skip_mode(clear_signatures, temp_factory, clear_now_and_after):
     '''Test skipping mode of signature'''
     clear_now_and_after([f'a_{i}.bak' for i in range(4)])