Test binary ignores arguments after the first unrecognized one

[Geod24]

What version of Go are you using (go version)?

go version go1.10.3 darwin/amd64
Also tested on linux/amd64 with 1.10.3 and 1.9.0

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

Irrelevant, but:

GOARCH="amd64"
GOCACHE="/Users/geod24/Library/Caches/go-build"
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/5l/cz1hkqt92nj3r44__pwfzdkm0000gn/T/go-build547748127=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do / expect to see / see instead?

TL;DR: The test binaries should not ignore arguments after the first unrecognized one, but only after --.

I built a test binary instrumented for code coverage.
I used the command go test -coverpkg=./... ./cmd -c -o experiment for building it.
I ran ./experiment some_argument -test.coverprofile=coverage.txt
=> No coverage.txt is generated
I ran ./experiment -test.coverprofile=coverage.txt some_argument
=> coverage.txt is generated as expected

The complete test, along with a more verbose description of my use case (integration tests with coverage reports integrated into a CI) is available in this Github repository.

[cznic]

From the flag package docs:

Flag parsing stops just before the first non-flag argument ("-" is a non-flag argument) or after the terminator "--".

(dup of #26104)

[Geod24]

I see, it comes from the package, hence why looking that the command documentation didn't yield any result. It's a rather odd behavior IMHO, but since it works as intended and is documented...