Improve tests and fix combined search

[hv0905]

• Improve tests for search and add test for advanced search
• Fix combined search to use correct vector and improve code readability

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 96.55172% with 1 line in your changes missing coverage. Please review.

Project coverage is 83.08%. Comparing base (14f2172) to head (8a6111d).

Files	Patch %	Lines
app/Controllers/search.py	96.42%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #39 +/- ## ========================================== + Coverage 80.42% 83.08% +2.66% ========================================== Files 29 29 Lines 1277 1271 -6 ========================================== + Hits 1027 1056 +29 + Misses 250 215 -35 ```

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[codeclimate[bot]]

Code Climate has analyzed commit 8a6111d0 and detected 0 issues on this pull request.

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