Add Scorer option to Query

[chrisdiana]

Add support for using custom scoring functions in a Redisearch query.

Closes #35

TFIDF is the default scoring function but this PR allows users to attach custom scoring functions to a Query object.

• TFIDF.DOCNORM
• BM25
• DISMAX
• DOCSCORE
• HAMMING

res = client.search(Query('foo').scorer('TFIDF.DOCNORM'))

https://oss.redislabs.com/redisearch/Scoring/

[codecov]

Codecov Report

Merging #113 (cbc87cb) into master (f3f11a4) will increase coverage by 0.14%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #113      +/-   ##
==========================================
+ Coverage   90.02%   90.17%   +0.14%     
==========================================
  Files          12       12              
  Lines        1675     1700      +25     
==========================================
+ Hits         1508     1533      +25     
  Misses        167      167              

Impacted Files	Coverage Δ
redisearch/query.py	90.50% <100.00%> (+0.37%)	⬆️
test/test.py	96.01% <100.00%> (+0.12%)	⬆️

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[chrisdiana]

@emmanuelkeller please let me know if there's anything you'd like me to add to this PR. thanks!

[ashtul]

Hi @chrisdiana,
Thank you for the PR.
Can you extend the test to include all types of scorers? In addition, add withscore so we can see the value changes.
Thanks

[chrisdiana]

Thanks @ashtul I've updated the PR with tests for all scorers with scores. Let me know if you want me to add anything else

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

[ashtul]

LGTM 👍
Thank you @chrisdiana

[ashtul]

@chrisdiana Why do we need this?

[chrisdiana]

@ashtul when you initially are setting up tests on a new repo and run make -C test/docker test PYTHON_VER=3 generated a ./deps directory that was dumped into my root path with "readies" inside it. It seemed like someething that wasn't cleaned up that maybe should have so I added to .gitignore in case the cleanup failed on others environments. I can remove it if you like though.