# C4 W1 A1: Tests failed on 1 cell(s)!

**URL:** <https://community.deeplearning.ai/t/c4-w1-a1-tests-failed-on-1-cell-s/56288>\
**Category:** Convolutional Neural Networks\
**Tags:** coursera-platform\
**Created:** [October 28, 2021, 2:59pm UTC](https://community.deeplearning.ai/t/c4-w1-a1-tests-failed-on-1-cell-s/56288 "2021-10-28T14:59:57Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Jason\_Fackler](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/jason_fackler/32/9763_2.png) [@Jason\_Fackler](https://community.deeplearning.ai/u/Jason_Fackler)\
**Post date:** [October 28, 2021, 2:59pm UTC](https://community.deeplearning.ai/t/c4-w1-a1-tests-failed-on-1-cell-s/56288/1 "2021-10-28T14:59:57Z")

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My submission only gets 75/100 even though it passes all the tests. I have tried starting from a clean copy and transferring over my code but that doesn’t work and don’t use any global variables inside the functions. I have no idea which test the grader is failing. The grader output is:

[ValidateApp | INFO] Validating ‘/home/jovyan/work/submitted/courseraLearner/W1A1/Convolution\_model\_Step\_by\_Step\_v1.ipynb’  
[ValidateApp | INFO] Executing notebook with kernel: python3  
Tests failed on 1 cell(s)! These tests could be hidden. Please check your submission.

Any ideas how I determine which test is failing?

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**Author:** ![reinoudbosch](https://avatars.discourse-cdn.com/v4/letter/r/22d042/32.png) [@reinoudbosch](https://community.deeplearning.ai/u/reinoudbosch)\
**Post date:** [October 28, 2021, 3:54pm UTC](https://community.deeplearning.ai/t/c4-w1-a1-tests-failed-on-1-cell-s/56288/2 "2021-10-28T15:54:32Z")

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Hi Jason\_Fackler,

Unfortunately the public tests do not detect all errors. If you want, feel free to send me your notebook with a direct message so I can have a look.

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**Author:** ![Hanqi\_Hua](https://avatars.discourse-cdn.com/v4/letter/h/e9c0ed/32.png) [@Hanqi\_Hua](https://community.deeplearning.ai/u/Hanqi_Hua)\
**Post date:** [December 25, 2021, 9:21pm UTC](https://community.deeplearning.ai/t/c4-w1-a1-tests-failed-on-1-cell-s/56288/3 "2021-12-25T21:21:27Z")

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I’m facing the same issue. Anyone knows how to fix this?

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**Author:** ![paulinpaloalto](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/paulinpaloalto/32/187_2.png) [@paulinpaloalto](https://community.deeplearning.ai/u/paulinpaloalto)\
**Post date:** [December 25, 2021, 10:04pm UTC](https://community.deeplearning.ai/t/c4-w1-a1-tests-failed-on-1-cell-s/56288/4 "2021-12-25T22:04:37Z")

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The most common error here is not implementing the stride in either _conv\_forward_ or _pool\_forward_ or both. The tests in the notebook do not catch that error. Take a careful look at your output values for the _stride = 2_ test case for _pool\_forward_: they all need to match, not just most of them. But the bug in the test cases is that they don’t “throw” even if you get some values wrong.