tx: fix PageCount update in allocate

[zrss]

tx: PageCount add up the count that we try to allocate

[codecov-io]

Codecov Report

Merging #65 into master will increase coverage by <.01%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master      #65      +/-   ##
==========================================
+ Coverage   85.56%   85.57%   +<.01%     
==========================================
  Files           9        9              
  Lines        1857     1858       +1     
==========================================
+ Hits         1589     1590       +1     
+ Misses        159      158       -1     
- Partials      109      110       +1

Impacted Files	Coverage Δ
db.go	82.79% <100%> (-0.04%)	⬇️
tx.go	76.82% <100%> (+0.6%)	⬆️
freelist.go	81.7% <50%> (-1.01%)	⬇️

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[xiang90]

@zrss can you add a test for this fix? thanks.

[zrss]

@xiang90

i add an accessible method for tx.allocate, and do not close the db file with MustClose method to skip MustCheck

[gyuho]

Why not creating another unit test file rather than exposing allocate method?

[zrss]

@gyuho

I added a new unit test file, but not sure whether the file name is appropriate. And there is a bolt_test package for test files, why not put them in the same package as bolt (such as freelist_test.go) ... just curious about that

[gyuho]

Defer to @xiang90

[xiang90]

lgtm