move request_builder into internal pkg (#304)

[vvatanabe]

Fix #304 (request_builder)
I moved the following files to the internal package.

request_builder.go -> internal/request_builder.go
request_builder_test.go -> internal/request_builder_test.go

Internal/request_builder_test.go was circularly referenced. So I moved the following test to client_test.go. They are tests for error cases resulting from calls to methods of openai.Client. So I decided it was appropriate to move them to client_test.go.

request_builder_test.go:TestClientReturnsRequestBuilderErrors -> client_test.go:TestClientReturnsRequestBuilderErrors
request_builder_test.go:TestReturnsRequestBuilderErrorsAddtion -> client_test.go:TestClientReturnsRequestBuilderErrorsAddtion

[codecov]

Codecov Report

Merging #329 (a6d1c8f) into master (62eb4be) will increase coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #329      +/-   ##
==========================================
+ Coverage   92.36%   92.45%   +0.08%     
==========================================
  Files          19       18       -1     
  Lines         655      636      -19     
==========================================
- Hits          605      588      -17     
+ Misses         37       35       -2     
  Partials       13       13              

Impacted Files	Coverage Δ
chat.go	100.00% <100.00%> (ø)
client.go	91.96% <100.00%> (ø)
completion.go	100.00% <100.00%> (ø)
edits.go	100.00% <100.00%> (ø)
embeddings.go	100.00% <100.00%> (ø)
engines.go	100.00% <100.00%> (+13.33%)	⬆️
files.go	82.35% <100.00%> (ø)
fine_tunes.go	100.00% <100.00%> (ø)
image.go	92.77% <100.00%> (ø)
models.go	100.00% <100.00%> (ø)
... and 1 more

... and 1 file with indirect coverage changes

[vvatanabe]

@sashabaranov Please check it.

[sashabaranov]

@vvatanabe thank you for the PR! Could you please update the tests so the coverage would not go down?

[vvatanabe]

@sashabaranov The following tests were added to increase coverage.

• internal/request_builder_test.go
• engines_test.go

FYI: We can view the codes not covered by the following commands in browser. It was very easy to detect.

$ go test -coverprofile=cover.out . /...
$ go tool cover -html=cover.out -o cover.html
$ open cover.html