skip removal tests in Python<3.8

tests/test_unasync.py

@@ -4,6 +4,7 @@
 import os
 import shutil
 import subprocess
+import sys
 
 import pytest
 
@@ -36,7 +37,8 @@ def test_rule_on_short_path():
 
 @pytest.mark.parametrize("source_file", TEST_FILES)
 def test_unasync(tmpdir, source_file):
-
+    if source_file == 'removals.py' and sys.version_info[2] < 8:
+        pytest.skip("unasync: remove feature is not supported in versions of Python less than 3.8")
     rule = unasync.Rule(fromdir=ASYNC_DIR, todir=str(tmpdir))
     rule._unasync_file(os.path.join(ASYNC_DIR, source_file))
 
@@ -56,6 +58,8 @@ def test_unasync_files(tmpdir):
     )
 
     for source_file in TEST_FILES:
+        if source_file == 'removals.py' and sys.version_info[2] < 8:
+            continue  # unasync-remove feature is not supported in versions of Python less than 3.8
         encoding = "latin-1" if "encoding" in source_file else "utf-8"
         with io.open(os.path.join(SYNC_DIR, source_file), encoding=encoding) as f:
             truth = f.read()