diff --git a/tests/test_conditions.py b/tests/test_conditions.py
index 2994c9d..e8a371b 100644
--- a/tests/test_conditions.py
+++ b/tests/test_conditions.py
@@ -235,7 +235,7 @@ def test_is_running_windows_found(monkeypatch: pytest.MonkeyPatch):
 
     monkeypatch.setattr(
         "subprocess.run",
-        lambda *a, **kw: MockResult(),
+        lambda *_, **__: MockResult(),
     )
     cond = BuiltinConditions.IS_RUNNING("explorer.exe")
     assert cond({}) is True
@@ -252,7 +252,7 @@ def test_is_running_windows_not_found(monkeypatch: pytest.MonkeyPatch):
 
     monkeypatch.setattr(
         "subprocess.run",
-        lambda *a, **kw: MockResult(),
+        lambda *_, **__: MockResult(),
     )
     cond = BuiltinConditions.IS_RUNNING("explorer.exe")
     assert cond({}) is False
@@ -268,7 +268,7 @@ def test_is_running_linux_found(monkeypatch: pytest.MonkeyPatch):
 
     monkeypatch.setattr(
         "subprocess.run",
-        lambda *a, **kw: MockResult(),
+        lambda *_, **__: MockResult(),
     )
     cond = BuiltinConditions.IS_RUNNING("nginx")
     assert cond({}) is True
@@ -284,7 +284,7 @@ def test_is_running_linux_not_found(monkeypatch: pytest.MonkeyPatch):
 
     monkeypatch.setattr(
         "subprocess.run",
-        lambda *a, **kw: MockResult(),
+        lambda *_, **__: MockResult(),
     )
     cond = BuiltinConditions.IS_RUNNING("nonexistent")
     assert cond({}) is False
diff --git a/tests/test_executors_edge_cases.py b/tests/test_executors_edge_cases.py
index 4553798..49b3e0e 100644
--- a/tests/test_executors_edge_cases.py
+++ b/tests/test_executors_edge_cases.py
@@ -3,6 +3,7 @@
 import asyncio
 import logging
 import sys
+from typing import Callable
 
 import pytest
 
@@ -326,7 +327,7 @@ def test_concurrency_key_thread() -> None:
 
     order = []
 
-    def make(name: str) -> callable:
+    def make(name: str) -> Callable[[], str]:
         def fn():
             order.append(f"{name}-start")
             time.sleep(0.1)
@@ -374,7 +375,7 @@ def test_dependency_strategy_basic() -> None:
     """dependency 策略应正确执行."""
     order = []
 
-    def make(name: str) -> callable:
+    def make(name: str) -> Callable[[], str]:
         def fn():
             order.append(name)
             return name
@@ -551,6 +552,7 @@ def test_unknown_strategy_raises() -> None:
     """未知 strategy 应抛 ValueError."""
     graph = px.Graph.from_specs([px.TaskSpec("a", fn=lambda: 1)])
     with pytest.raises(ValueError, match="Unknown strategy"):
+        # pyrefly: ignore [bad-argument-type]
         px.run(graph, strategy="unknown_strategy")
 
 
diff --git a/tests/test_system.py b/tests/test_system.py
index 5bf751c..be530a1 100644
--- a/tests/test_system.py
+++ b/tests/test_system.py
@@ -26,12 +26,13 @@ def test_clr_executes_on_linux(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr(
         subprocess,
         "run",
-        lambda cmd, **kw: ran.append(cmd),
+        lambda *cmd, **__: ran.append(cmd),
     )
 
     spec = clr()
+    assert spec.fn is not None
     spec.fn()
-    assert ran == [["clear"]]
+    assert ran == [(["clear"],)]
 
 
 def test_clr_executes_on_windows(monkeypatch: pytest.MonkeyPatch) -> None:
@@ -43,12 +44,13 @@ def test_clr_executes_on_windows(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr(
         subprocess,
         "run",
-        lambda cmd, **kw: ran.append(cmd),
+        lambda *cmd, **__: ran.append(cmd),
     )
 
     spec = clr()
+    assert spec.fn is not None
     spec.fn()
-    assert ran == [["cls"]]
+    assert ran == [(["cls"],)]
 
 
 def test_reset_icon_cache_non_windows(monkeypatch: pytest.MonkeyPatch, capsys: pytest.CaptureFixture[str]) -> None:
@@ -83,31 +85,39 @@ def test_setenv_creates_task_spec() -> None:
 
 def test_setenv_sets_environment_variable(monkeypatch: pytest.MonkeyPatch) -> None:
     """setenv() 应设置环境变量。"""
-    spec = setenv("TEST_VAR", "test_value")
+    spec = setenv("PYFLOWX_TEST_VAR_1", "test_value")
+    assert spec.fn is not None
     spec.fn()
-    assert os.environ["TEST_VAR"] == "test_value"
+    assert os.environ["PYFLOWX_TEST_VAR_1"] == "test_value"
+    # Clean up
+    del os.environ["PYFLOWX_TEST_VAR_1"]
 
 
 def test_setenv_default_not_overwrite(monkeypatch: pytest.MonkeyPatch) -> None:
     """setenv(default=True) 不应覆盖已存在的环境变量。"""
-    os.environ["TEST_VAR_EXISTS"] = "original"
-    spec = setenv("TEST_VAR_EXISTS", "new_value", default=True)
+    os.environ["PYFLOWX_TEST_VAR_EXISTS"] = "original"
+    spec = setenv("PYFLOWX_TEST_VAR_EXISTS", "new_value", default=True)
+    assert spec.fn is not None
     spec.fn()
-    assert os.environ["TEST_VAR_EXISTS"] == "original"
+    assert os.environ["PYFLOWX_TEST_VAR_EXISTS"] == "original"
+    # Clean up
+    del os.environ["PYFLOWX_TEST_VAR_EXISTS"]
 
 
 def test_setenv_default_sets_when_missing() -> None:
     """setenv(default=True) 应在缺失时设置环境变量。"""
     # Ensure variable does not exist
-    if "PYFLOWX_TEST_VAR_MISSING" in os.environ:
-        del os.environ["PYFLOWX_TEST_VAR_MISSING"]
+    var_name = "PYFLOWX_TEST_VAR_MISSING"
+    if var_name in os.environ:
+        del os.environ[var_name]
 
-    spec = setenv("PYFLOWX_TEST_VAR_MISSING", "default_value", default=True)
+    spec = setenv(var_name, "default_value", default=True)
+    assert spec.fn is not None
     spec.fn()
-    assert os.environ["PYFLOWX_TEST_VAR_MISSING"] == "default_value"
+    assert os.environ[var_name] == "default_value"
 
     # Clean up after test
-    del os.environ["PYFLOWX_TEST_VAR_MISSING"]
+    del os.environ[var_name]
 
 
 def test_which_creates_task_spec() -> None:
@@ -127,10 +137,11 @@ def test_which_linux_found(monkeypatch: pytest.MonkeyPatch, capsys: pytest.Captu
     monkeypatch.setattr(
         subprocess,
         "run",
-        lambda cmd, **kw: MockResult(),
+        lambda *_, **__: MockResult(),
     )
 
     spec = which("python")
+    assert spec.fn is not None
     spec.fn()
     captured = capsys.readouterr()
     assert "python ->" in captured.out
@@ -148,10 +159,11 @@ def test_which_windows_found(monkeypatch: pytest.MonkeyPatch, capsys: pytest.Cap
     monkeypatch.setattr(
         subprocess,
         "run",
-        lambda cmd, **kw: MockResult(),
+        lambda *_, **__: MockResult(),
     )
 
     spec = which("python")
+    assert spec.fn is not None
     spec.fn()
     captured = capsys.readouterr()
     assert "python ->" in captured.out
@@ -169,10 +181,11 @@ def test_which_not_found(monkeypatch: pytest.MonkeyPatch, capsys: pytest.Capture
     monkeypatch.setattr(
         subprocess,
         "run",
-        lambda cmd, **kw: MockResult(),
+        lambda *_, **__: MockResult(),
     )
 
     spec = which("nonexistent_cmd")
+    assert spec.fn is not None
     spec.fn()
     captured = capsys.readouterr()
     assert "nonexistent_cmd -> 未找到" in captured.out
diff --git a/tests/test_task.py b/tests/test_task.py
index f0d48a4..e1edd9d 100644
--- a/tests/test_task.py
+++ b/tests/test_task.py
@@ -127,6 +127,7 @@ def test_should_execute_condition_exception_returns_false() -> None:
     spec = TaskSpec("a", _fn, conditions=(bad_condition,))
     should_run, reason = spec.should_execute({})
     assert should_run is False
+    # pyrefly: ignore [not-iterable]
     assert "匿名条件(执行错误)" in reason
 
 
@@ -135,6 +136,7 @@ def test_should_execute_condition_lambda_name() -> None:
     spec = TaskSpec("a", _fn, conditions=(lambda _ctx: False,))
     should_run, reason = spec.should_execute({})
     assert should_run is False
+    # pyrefly: ignore [not-iterable]
     assert "<lambda>" in reason
 
 
@@ -143,6 +145,7 @@ def test_should_execute_skip_if_missing_cmd_not_found() -> None:
     spec = TaskSpec("a", cmd=["nonexistent_cmd_xyz"], skip_if_missing=True)
     should_run, reason = spec.should_execute({})
     assert should_run is False
+    # pyrefly: ignore [not-iterable]
     assert "命令不存在" in reason