Fixes exception in preview using regexp search and regexp search without specified field

[k3KAW8Pnf7mkmdSMPHz27]

Fixes #6777 . The issue originates in how the JavaScript regexp is created in PreviewViewer#highlightSearchPattern.

1. Fixes the use of regexp while searching for one term (e.g., Liu.*)
2. Fixes exception in the preview when forward slash is used in the regexp

• Change in CHANGELOG.md described (if applicable)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked documentation: Is the information available and up to date? If not created an issue at https://github.com/JabRef/user-documentation/issues or, even better, submitted a pull request to the documentation repository.

[k3KAW8Pnf7mkmdSMPHz27]

Is there a good spot to put test cases for this issue?

[k3KAW8Pnf7mkmdSMPHz27]

This PR can be made better by some larger reformatting but there might not be a point to doing it given that the code should be completely replaced by Lucene.

[Siedlerchr]

I think it's not too important to have the highlighting that accurate for each complicated regex and yeah in the longterm we plan to use/convert to lucence. And thanks for finding the issue with the grammar based search + the regex!

[Siedlerchr]

As you are at the search code and as you also worked on the unicode normalization, can you maybe check that issue here as well? #6815

[k3KAW8Pnf7mkmdSMPHz27]

As you are at the search code and as you also worked on the unicode normalization, can you maybe check that issue here as well? #6815

Sure, will do !

[k3KAW8Pnf7mkmdSMPHz27]

I think it's not too important to have the highlighting that accurate for each complicated regex and yeah in the longterm we plan to use/convert to lucence.

I agree, and I haven't really looked into this in enough detail to contribute. There are definitively still going to be other issues after this PR. It just aims to address the most obvious cases of the / exception.

And thanks for finding the issue with the grammar based search + the regex!

Thank you for the sanity check and help, it is both appreciated and saves me time ^^

[koppor]

At first, LGTM.

Minor issue with a magic string replacmenet 😇

May I ask whether its possible to add a test case for the fixed functionality?

[k3KAW8Pnf7mkmdSMPHz27]

May I ask whether its possible to add a test case for the fixed functionality?

I'll look into it tomorrow. I don't have any experience writing tests for this type of code but there should be some "template" I can use elsewhere.

[Siedlerchr]

Regarding tests, you are lucky, as there is already one: https://github.com/JabRef/jabref/blob/master/src/test/java/org/jabref/model/search/rules/ContainBasedSearchRuleTest.java
(Please also refactor the BibEntry to "withField" )

[k3KAW8Pnf7mkmdSMPHz27]

I keep running into the same issue with creating a PreviewViewerTest.

BibDatabaseContext databaseContext = new BibDatabaseContext();
StateManager stateManager = new StateManager();
stateManager.setSearchQuery(new SearchQuery("test", false, false));

PreviewViewer pw = new PreviewViewer(databaseContext, null, stateManager);

As soon as I call the constructor I get a java.lang.ExceptionInInitializerError (i.e., before it enters the constructor)

[Siedlerchr]

If you want to test something on the javafx thread, you need to use the testfx extensions and declare it as GUI test:
See as an example the SourceTabTest under gui.entryeditor.
But that is complicated. I would rather merge this one as it is now. Feel free to create another PR with a gui test

[k3KAW8Pnf7mkmdSMPHz27]

@Siedlerchr @koppor thank you both for your reviews! They are very appreciated!

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If you want to test something on the javafx thread, you need to use the testfx extensions and declare it as GUI test:
See as an example the SourceTabTest under gui.entryeditor.
But that is complicated. I would rather merge this one as it is now. Feel free to create another PR with a gui test

Great! In that case, I'll put adding a test case for this issue on my todo-list for later.
Thank you for linking SourceTabTest, now I know where to start digging 😃
I suspect I'll have opportunities to practice writing GUI tests soon X)