# Problems using test-filter

**URL:** https://forum.duplicati.com/t/problems-using-test-filter/6101
**Category:** Support
**Created:** [January 23, 2019, 12:08pm UTC](https://forum.duplicati.com/t/problems-using-test-filter/6101 "2019-01-23T12:08:38Z")
**Posts on this page:** 1
**Showing post:** 7

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### Author: ![ts678](https://forum.duplicati.com/letter_avatar_proxy/v4/letter/t/8491ac/32.png) [@ts678](https://forum.duplicati.com/u/ts678)
#### Post date: [January 25, 2019, 2:35am UTC](https://forum.duplicati.com/t/problems-using-test-filter/6101/7 "2019-01-25T02:35:02Z")

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That results stack trace looks similar to [Backups fail with error: Object reference not set to an instance of an object](https://forum.duplicati.com/t/backups-fail-with-error-object-reference-not-set-to-an-instance-of-an-object/5570/9?u=ts678) except that yours started in TestFilter while the other started in Backup. They ended in the same way, which is possibly a failure in collecting the output lines, but my previous attempts to debug the failure dead-ended. Interestingly both failures are Linux. Sometimes updating to latest mono can solve surprising things. [[Solved] Failed to connect: Only http or https scheme is allowed in 2.0.4.10\_canary\_2018-12-29](https://forum.duplicati.com/t/solved-failed-to-connect-only-http-or-https-scheme-is-allowed-in-2-0-4-10-canary-2018-12-29/6020/6?u=ts678) is the latest case where I wished I’d suggested trying it. I’m not sure if you want to try updating mono though.

If you happen to have a Windows system showing a stack trace like that, my chances of debug get higher. You could also file an [issue](https://github.com/duplicati/duplicati/issues) for the developers, especially if you can come up with a very simple test case.

An alternative suggestion is to try real shell instead of GUI one, being careful to quote strings as necessary. While I’d like to solve the `Object reference` failure, I think I’ll have better luck at getting test-filters running. Following your steps didn’t break Commandline (but my /root is almost certainly smaller – does it matter?) however one oddity is that adding the cache exclude broke the Duplicati exclude. Under shell, it still works:

```
# duplicati-cli test-filters /root/ --exclude="/*root/.config/Duplicati*/" --exclude="*/.cache" | grep Duplicati
Excluding path due to filter: /root/.config/Duplicati/ => (/*root/.config/Duplicati*/) || (*/.cache)
# 
# duplicati-cli test-filters /root/ --exclude="*/.cache" --exclude="/*root/.config/Duplicati*/" | grep Duplicati
Excluding path due to filter: /root/.config/Duplicati/ => (*/.cache) || (/*root/.config/Duplicati*/)
# 

```

I haven’t yet tried reversing order in the GUI. I wonder if this unusual case of repeating options won’t work? OK, I had to try reversing, and it seems like perhaps the last --exclude option it gets is the only one it does. Seems like a possible bug (although a somewhat obscure one) in however Commandline is implemented. For the clear bug of NullReferenceException, does it also fail with short output e.g. /root/.config/ not /root/?

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