How do I set environment variables during the build in docker

Question

I've tried unsuccessfully to set environment variables in a Docker container during the build. Using the run command to set them works, but I need to do it during the build.

Here's dockerfile

FROM ubuntu:latest
ARG TEST_ENV=something

My build command

docker build -t --build-arg TEST_ENV="test" myimage .

My run command

docker run -dit myimage

Using below command to check available environment variables

docker exec containerid printenv

My result

PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=e49c1abfd58b
TERM=xterm
no_proxy=*.local, 169.254/16
HOME=/root

TEST_ENV is not present here