diff --git a/tests/test.py b/tests/test.py
index cc21570..df1263d 100644
--- a/tests/test.py
+++ b/tests/test.py
@@ -55,75 +55,64 @@ class JudgerTest(TestCase):
 
     def _judger_cpu_time_args_check(self):
         with self.assertRaisesRegexp(ValueError, "max_cpu_time must > 1 ms"):
-            judger.run(path="/bin/ls",
-                       in_file=os.path.join(os.path.dirname(os.path.abspath(__file__)), "/dev/null"),
+            judger.run(path="/bin/true", in_file="/dev/null",
                        out_file="/dev/null", max_cpu_time=-1, max_memory=200000000,
                        env=["aaa=123"], use_sandbox=False, use_nobody=False)
 
     def _judger_memory_args_check(self):
         with self.assertRaisesRegexp(ValueError, "max_memory must > 16M"):
-            judger.run(path="/bin/ls",
-                       in_file=os.path.join(os.path.dirname(os.path.abspath(__file__)), "/dev/null"),
+            judger.run(path="/bin/true", in_file="/dev/null",
                        out_file="/dev/null", max_cpu_time=1000, max_memory=100,
                        env=["aaa=123"], use_sandbox=True, use_nobody=True)
 
     def _judger_exec_file_args_check(self):
-        with self.assertRaisesRegexp(ValueError, "in_file does not exist"):
-            judger.run(path="/bin/xxx",
-                       in_file=os.path.join(os.path.dirname(os.path.abspath(__file__)), "/dev/null"),
+        with self.assertRaisesRegexp(ValueError, "Exec file does not exist"):
+            judger.run(path="/bin/not_found", in_file="/dev/null",
                        out_file="/dev/null", max_cpu_time=1000, max_memory=200000000,
                        env=["aaa=123"], use_sandbox=True, use_nobody=True)
 
     def _judger_in_file_args_check(self):
         with self.assertRaisesRegexp(ValueError, "in_file does not exist"):
-            judger.run(path="/bin/xxx",
-                       in_file="/dev/xxx",
+            judger.run(path="/bin/true", in_file="/dev/xxx",
                        out_file="/dev/null", max_cpu_time=1000, max_memory=200000000,
                        env=["aaa=123"], use_sandbox=True, use_nobody=True)
 
     def _judger_args_args_check(self):
         with self.assertRaisesRegexp(ValueError, "args must be a list"):
-            judger.run(path="/bin/ls",
-                       in_file="/dev/null",
+            judger.run(path="/bin/ls", in_file="/dev/null",
                        out_file="/dev/null", max_cpu_time=1000, max_memory=200000000,
                        args=123, use_sandbox=True, use_nobody=True)
 
         with self.assertRaisesRegexp(ValueError, "arg in args must be a string"):
-            judger.run(path="/bin/ls",
-                       in_file="/dev/null",
+            judger.run(path="/bin/ls", in_file="/dev/null",
                        out_file="/dev/null", max_cpu_time=1000, max_memory=200000000,
                        args=["123", {"a": "b"}], use_sandbox=True, use_nobody=True)
 
         with self.assertRaisesRegexp(ValueError, "Number of args must < 95"):
-            judger.run(path="/bin/ls",
-                       in_file="/dev/null",
+            judger.run(path="/bin/ls", in_file="/dev/null",
                        out_file="/dev/null", max_cpu_time=1000, max_memory=200000000,
                        args=["123"] * 200, use_sandbox=True, use_nobody=True)
 
     def _judger_env_args_check(self):
         with self.assertRaisesRegexp(ValueError, "env must be a list"):
-            judger.run(path="/bin/ls",
-                       in_file="/dev/null",
+            judger.run(path="/bin/true", in_file="/dev/null",
                        out_file="/dev/null", max_cpu_time=1000, max_memory=200000000,
                        env=123, use_sandbox=True, use_nobody=True)
 
         with self.assertRaisesRegexp(ValueError, "env item must be a string"):
-            judger.run(path="/bin/ls",
-                       in_file="/dev/null",
+            judger.run(path="/bin/ls", in_file="/dev/null",
                        out_file="/dev/null", max_cpu_time=1000, max_memory=200000000,
                        env=["123", {"a": "b"}], use_sandbox=True, use_nobody=True)
 
         with self.assertRaisesRegexp(ValueError, "Number of env must < 95"):
-            judger.run(path="/bin/ls",
-                       in_file="/dev/null",
+            judger.run(path="/bin/true", in_file="/dev/null",
                        out_file="/dev/null", max_cpu_time=1000, max_memory=200000000,
                        env=["123=345"] * 200, use_sandbox=True, use_nobody=True)
 
     def _judger_user_args_check(self):
         os.setuid(pwd.getpwnam("nobody").pw_uid)
         with self.assertRaisesRegexp(ValueError, "Root user is required when use_nobody=True"):
-            judger.run(path="/bin/ls",
-                       in_file=os.path.join(os.path.dirname(os.path.abspath(__file__)), "/dev/null"),
+            judger.run(path="/bin/ls", in_file="/dev/null",
                        out_file="/dev/null", max_cpu_time=2000, max_memory=200000000,
                        env=["aaa=123"], use_sandbox=True, use_nobody=True)