diff --git a/tests/test_config_and_args.py b/tests/test_config_and_args.py
index d96b83f..766d704 100644
--- a/tests/test_config_and_args.py
+++ b/tests/test_config_and_args.py
@@ -262,7 +262,7 @@ def test_200_from_config_subprocess(tmp_path: Path):
     assert res.stdout == err_msg.encode("ascii")
 
 
-def test_trio200_from_config_subprocess(tmp_path: Path):
+def test_async200_from_config_subprocess(tmp_path: Path):
     err_msg = _test_async200_from_config_common(tmp_path, code="trio200")
     res = subprocess.run(["flake8"], cwd=tmp_path, capture_output=True, check=False)
     assert res.returncode == 1
@@ -273,20 +273,55 @@ def test_trio200_from_config_subprocess(tmp_path: Path):
     assert res.stdout == err_msg.encode("ascii")
 
 
+def test_async200_from_config_subprocess_cli_ignore(tmp_path: Path):
+    _ = _test_async200_from_config_common(tmp_path)
+    res = subprocess.run(
+        ["flake8", "--ignore=ASYNC200"],
+        cwd=tmp_path,
+        capture_output=True,
+        check=False,
+        encoding="utf8",
+    )
+    assert not res.stderr
+    assert not res.stdout
+    assert res.returncode == 0
+
+
 def test_900_default_off(capsys: pytest.CaptureFixture[str]):
     from flake8.main.cli import main
 
     returnvalue = main(
         argv=[
-            "tests/trio900.py",
+            "tests/eval_files/async900.py",
         ]
     )
     out, err = capsys.readouterr()
     assert returnvalue == 1
     assert not err
+    assert "E501" in out
     assert "ASYNC900" not in out
 
 
+def test_910_can_be_selected(tmp_path: Path):
+    myfile = tmp_path.joinpath("foo.py")
+    myfile.write_text("""async def foo():\n    print()""")
+
+    res = subprocess.run(
+        ["flake8", "--select=ASYNC910", "foo.py"],
+        cwd=tmp_path,
+        capture_output=True,
+        check=False,
+        encoding="utf8",
+    )
+
+    assert not res.stderr
+    assert res.stdout == (
+        "foo.py:1:1: ASYNC910 exit from async function with no guaranteed"
+        " checkpoint or exception since function definition on line 1.\n"
+    )
+    assert res.returncode == 1
+
+
 def test_enable(
     tmp_path: Path, monkeypatch: pytest.MonkeyPatch, capsys: pytest.CaptureFixture[str]
 ):
@@ -418,12 +453,12 @@ def test_disable_noqa_ast(
     )
 
 
-@pytest.mark.xfail(reason="flake8>=6 enforces three-letter error codes in config")
-def test_config_ignore_error_code(tmp_path: Path) -> None:
+def test_config_select_error_code(tmp_path: Path) -> None:
     assert tmp_path.joinpath(".flake8").write_text(
         """
 [flake8]
-ignore = ASYNC100
+select = ASYNC100
+extend-select = ASYNC100
 """
     )
     res = subprocess.run(
@@ -433,6 +468,49 @@ def test_config_ignore_error_code(tmp_path: Path) -> None:
     assert res.returncode == 0
 
 
+# flake8>=6 enforces three-letter error codes in config
+def test_config_ignore_error_code(tmp_path: Path) -> None:
+    assert tmp_path.joinpath(".flake8").write_text(
+        """
+[flake8]
+ignore = ASYNC100
+"""
+    )
+    res = subprocess.run(
+        ["flake8", "--help"],
+        cwd=tmp_path,
+        capture_output=True,
+        check=False,
+        encoding="utf8",
+    )
+    assert (
+        "Error code 'ASYNC100' supplied to 'ignore' option does not match" in res.stderr
+    )
+    assert res.returncode == 1
+
+
+# flake8>=6 enforces three-letter error codes in config
+def test_config_extend_ignore_error_code(tmp_path: Path) -> None:
+    assert tmp_path.joinpath(".flake8").write_text(
+        """
+[flake8]
+extend-ignore = ASYNC100
+"""
+    )
+    res = subprocess.run(
+        ["flake8", "--help"],
+        cwd=tmp_path,
+        capture_output=True,
+        check=False,
+        encoding="utf8",
+    )
+    assert (
+        "Error code 'ASYNC100' supplied to 'extend-ignore' option does not match"
+        in res.stderr
+    )
+    assert res.returncode == 1
+
+
 # but make sure we can disable selected codes
 def test_config_disable_error_code(tmp_path: Path) -> None:
     # select ASYNC200 and create file that induces ASYNC200