Fix sqlalchemy query error of test_postgres.py (Fix #538)

[YasushiMiyata]

Description of the problems or issues

Is your pull request related to a problem? Please describe.
See #538

Does your pull request fix any issue.
See #538

Description of the proposed changes

Fix sqlalchemy query building on tests/test_postgres.py::test_cand_gen_cascading_delete.
Before this fixing, this test code tried delete query for deleting one data from PartTemp table, but sqlalchemy create unexecutable query to refer candidate.id from PartTemp table although this query does not use candidate.id.
Fix is changing query builder codes not to refer candidate.id.

Test plan

Execute tests/test_postgres.py::test_cand_gen_cascading_delete.

Checklist

• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.
• I have updated the CHANGELOG.rst accordingly.

[YasushiMiyata]

This fixs issue #538 and pytest on github was successful. However, the error occurs in the process of "test (macos-latest, 3.6)";

Warning: Cache service responded with 503 during chunk upload.
events.js:187
      throw er; // Unhandled 'error' event

Can I fix it myself? Please support.

[senwu]

This fixs issue #538 and pytest on github was successful. However, the error occurs in the process of "test (macos-latest, 3.6)";

Warning: Cache service responded with 503 during chunk upload.
events.js:187
      throw er; // Unhandled 'error' event

Can I fix it myself? Please support.

Please fix it. Thanks!!!

[lukehsiao]

@YasushiMiyata I just re-ran the jobs and it appears to have passed. I don't think that error was caused by you.

[YasushiMiyata]

@senwu , @lukehsiao Thank you for checking and your comments. I also found my request passed.
The previous error may be something temporary unavailable on network.

[lukehsiao]

nit: can we call this variable candidate or cand rather than d?

[YasushiMiyata]

I think candidate is better than d. I correct it.
As a side note, I was intended that d denotes delete row of PartTemp table. However, this d also means delete candidate. So, I update d to candidate. Thank you for your suggestion!

[codecov-commenter]

Codecov Report

Merging #539 (642389f) into master (433a75d) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #539   +/-   ##
=======================================
  Coverage   86.02%   86.02%           
=======================================
  Files          92       92           
  Lines        4773     4773           
  Branches      899      899           
=======================================
  Hits         4106     4106           
  Misses        476      476           
  Partials      191      191           

Flag	Coverage Δ
unittests	86.02% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.