Correct FP rounding errors

[stevennic]

Following up on #519, correcting a few more rounding bugs I found.

[codecov]

Codecov Report

Merging #539 into master will increase coverage by 0.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #539      +/-   ##
==========================================
+ Coverage   82.99%   83.01%   +0.01%     
==========================================
  Files         132      132              
  Lines       29621    29621              
==========================================
+ Hits        24585    24590       +5     
+ Misses       5036     5031       -5

Impacted Files	Coverage Δ
src/whoosh/matching/binary.py	71.88% <0%> (ø)	⬆️
src/whoosh/collectors.py	92.64% <0%> (-0.22%)	⬇️
tests/test_collector.py	99.41% <0%> (+0.58%)	⬆️
src/whoosh/index.py	76.01% <0%> (+1.55%)	⬆️

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[stevennic]

I can't explain the codecov/patch problem. Is it a deal breaker for merging?

[nijel]

0% coverage for patch, should mean that you changes are not covered by tests at all. It would be great if you could add tests covering those cases.

[stevennic]

I always do, but in this case I just changed 3 logical operators in existing code, so I don't see how coverage could change at all. I read some issues in codecov forums echoing similar strange behavior with 0% codecov/patch but I can't tell if it's related.

[nijel]

The coverage has not changed (what can be seen on codecov/project check). The problem is that the code you've changed is not covered by tests at all.

PS: I'm not saying this should block accepting this, I'm just explaining why Codecov complains.

[stevennic]

I see, so it was uncovered all along?

[nijel]

Exactly. You've touched code paths which are not tested at all. It's not that hard as there is about 30% of that file not covered by tests, see https://codecov.io/gh/whoosh-community/whoosh/src/master/src/whoosh/matching/binary.py

[stevennic]

Ah I see! Good opportunity to add unit tests then. I'll try to get to that. Thanks for the clarification.

[stevennic]

I'm unable to find a unit test that covers this code path at this time. Given that this patch fixes a found bug with minimal changes, I propose it be merged anyway. We can work on increasing code coverage separately.