diff --git a/joj3_config_generator/transformers/task.py b/joj3_config_generator/transformers/task.py
index 096d035..3dcbcbe 100644
--- a/joj3_config_generator/transformers/task.py
+++ b/joj3_config_generator/transformers/task.py
@@ -200,11 +200,12 @@ def fix_diff(
         )
         if cmd.args == executor.with_.default.args:
             cmd.args = None
-        if cmd.cpu_limit == executor.with_.default.cpu_limit:
+        # duplicate with the fallback case in executor.with_
+        if cmd.cpu_limit == const.DEFAULT_CPU_LIMIT:
             cmd.cpu_limit = None
-        if cmd.clock_limit == executor.with_.default.clock_limit:
+        if cmd.clock_limit == 2 * const.DEFAULT_CPU_LIMIT:
             cmd.clock_limit = None
-        if cmd.memory_limit == executor.with_.default.memory_limit:
+        if cmd.memory_limit == const.DEFAULT_MEMORY_LIMIT:
             cmd.memory_limit = None
         if cmd.proc_limit == executor.with_.default.proc_limit:
             cmd.proc_limit = None
@@ -224,18 +225,11 @@ def fix_diff(
         parser_cases.append(parser_case)
     for case in default_cases:
         cmd = result.OptionalCmd(
-            stdin=result.LocalFile(src=str(base_dir / f"{case}.in"))
+            stdin=result.LocalFile(src=str(base_dir / f"{case}.in")),
+            cpu_limit=None,
+            clock_limit=None,
+            memory_limit=None,
         )
-        if cmd.args == executor.with_.default.args:
-            cmd.args = None
-        if cmd.cpu_limit == executor.with_.default.cpu_limit:
-            cmd.cpu_limit = None
-        if cmd.clock_limit == executor.with_.default.clock_limit:
-            cmd.clock_limit = None
-        if cmd.memory_limit == executor.with_.default.memory_limit:
-            cmd.memory_limit = None
-        if cmd.proc_limit == executor.with_.default.proc_limit:
-            cmd.proc_limit = None
         stage_cases.append(cmd)
         parser_case = result.DiffCasesConfig(
             outputs=[
diff --git a/tests/convert/diff/task.json b/tests/convert/diff/task.json
index e463c02..96291fa 100644
--- a/tests/convert/diff/task.json
+++ b/tests/convert/diff/task.json
@@ -26,17 +26,17 @@
                             ],
                             "stdout": {
                                 "name": "stdout",
-                                "max": 33554432,
+                                "max": 10485760,
                                 "pipe": true
                             },
                             "stderr": {
                                 "name": "stderr",
-                                "max": 33554432,
+                                "max": 10485760,
                                 "pipe": true
                             },
-                            "cpuLimit": 1000000000,
-                            "clockLimit": 2000000000,
-                            "memoryLimit": 68157440,
+                            "cpuLimit": 3000000000,
+                            "clockLimit": 6000000000,
+                            "memoryLimit": 10485760,
                             "stackLimit": 0,
                             "procLimit": 50,
                             "cpuRateLimit": 0,
@@ -84,26 +84,22 @@
                             {
                                 "stdin": {
                                     "src": "/home/tt/.config/joj/diff/case9.in"
-                                },
-                                "memoryLimit": 268435456
+                                }
                             },
                             {
                                 "stdin": {
                                     "src": "/home/tt/.config/joj/diff/task1/subtask1/case11.in"
-                                },
-                                "memoryLimit": 268435456
+                                }
                             },
                             {
                                 "stdin": {
                                     "src": "/home/tt/.config/joj/diff/task1/subtask1/case10.in"
-                                },
-                                "memoryLimit": 268435456
+                                }
                             },
                             {
                                 "stdin": {
                                     "src": "/home/tt/.config/joj/diff/task1/case5.in"
-                                },
-                                "memoryLimit": 268435456
+                                }
                             },
                             {
                                 "stdin": {
diff --git a/tests/convert/diff/task.toml b/tests/convert/diff/task.toml
index bb18497..fc28cd7 100644
--- a/tests/convert/diff/task.toml
+++ b/tests/convert/diff/task.toml
@@ -8,7 +8,10 @@ release.begin_time = 2024-12-29 23:59:59+08:00
 name = "[joj] ex2-asan"
 command="./h7/build/ex2-asan -a"
 files.import = [ "h7/build/ex2-asan" ]
-limit.mem = "65m"
+limit.cpu = "3s"
+limit.mem = "10m"
+limit.stdout = "10m"
+limit.stderr = "10m"
 
 parsers = [ "diff", "result-detail" ]
 result-detail.exitstatus = true
@@ -16,7 +19,6 @@ result-detail.stderr = true
 
 diff.default_score = 100
 
-# will be removed as long as the name is fixed
 case0.diff.output.score = 5
 case0.limit.cpu = "1s"
 case0.limit.mem = "2m"