tmt does not like if entrypoint is not standard

[thrix]

While working on our CLI tool, I found this annoyance, if I have ENTRYPOINT set, tmt starts the container with the command and just exits, subsequent commands file. The error is cryptic:

❯ tmt run -dddvvv
Using tree '/home/mvadkert/git/gitlab.com/testing-farm/cli'.
/var/tmp/tmt/run-007
tmt version: 1.9.0 (599b9a1)
Read file '/var/tmp/tmt/run-007/run.yaml'.
Run data not found.
Enabled steps: discover, report, finish, provision, execute and prepare
    Sync the worktree to '/var/tmp/tmt/run-007/plans/sanity/tree'.
    Run command 'rsync -ar --exclude .git /home/mvadkert/git/gitlab.com/testing-farm/cli/ /var/tmp/tmt/run-007/plans/sanity/tree'.
Found 1 plan.
Write file '/var/tmp/tmt/run-007/run.yaml'.

/plans/sanity
summary: Sanity test plan
info
    environment: {}
    context: {}
wake
    discover
        Read file '/var/tmp/tmt/run-007/plans/sanity/discover/step.yaml'.
        Step data not found.
        Read file '/var/tmp/tmt/run-007/plans/sanity/discover/tests.yaml'.
        Discovered tests not found.
        Using the 'DiscoverFmf' plugin for the 'fmf' method.
        status: todo
        Write file '/var/tmp/tmt/run-007/plans/sanity/discover/step.yaml'.
        Write file '/var/tmp/tmt/run-007/plans/sanity/discover/tests.yaml'.
    provision
        Read file '/var/tmp/tmt/run-007/plans/sanity/provision/step.yaml'.
        Step data not found.
        Read file '/var/tmp/tmt/run-007/plans/sanity/provision/guests.yaml'.
        Provisioned guests not found.
        Using the 'ProvisionPodman' plugin for the 'container' method.
        status: todo
        Write file '/var/tmp/tmt/run-007/plans/sanity/provision/step.yaml'.
        Write file '/var/tmp/tmt/run-007/plans/sanity/provision/guests.yaml'.
    prepare
        Read file '/var/tmp/tmt/run-007/plans/sanity/prepare/step.yaml'.
        Step data not found.
        Using the 'PrepareShell' plugin for the 'shell' method.
        status: todo
        Write file '/var/tmp/tmt/run-007/plans/sanity/prepare/step.yaml'.
    execute
        Read file '/var/tmp/tmt/run-007/plans/sanity/execute/step.yaml'.
        Step data not found.
        Read file '/var/tmp/tmt/run-007/plans/sanity/execute/results.yaml'.
        Test results not found.
        Using the 'ExecuteInternal' plugin for the 'tmt' method.
        status: todo
        Write file '/var/tmp/tmt/run-007/plans/sanity/execute/step.yaml'.
        Write file '/var/tmp/tmt/run-007/plans/sanity/execute/results.yaml'.
    report
        Read file '/var/tmp/tmt/run-007/plans/sanity/report/step.yaml'.
        Step data not found.
        Report step always force mode enabled.
        Clean up workdir '/var/tmp/tmt/run-007/plans/sanity/report'.
        status: todo
        Using the 'ReportDisplay' plugin for the 'display' method.
        Write file '/var/tmp/tmt/run-007/plans/sanity/report/step.yaml'.
    finish
        Read file '/var/tmp/tmt/run-007/plans/sanity/finish/step.yaml'.
        Step data not found.
        Using the 'FinishShell' plugin for the 'shell' method.
        status: todo
        Write file '/var/tmp/tmt/run-007/plans/sanity/finish/step.yaml'.
    action
go
    discover
        workdir: /var/tmp/tmt/run-007/plans/sanity/discover
        how: fmf
        order: 50
            Run command 'git rev-parse --show-toplevel'.
            out: /home/mvadkert/git/gitlab.com/testing-farm/cli
        directory: /home/mvadkert/git/gitlab.com/testing-farm/cli
            Copy '/home/mvadkert/git/gitlab.com/testing-farm/cli' to '/var/tmp/tmt/run-007/plans/sanity/discover/default/tests'.
            Run command 'git rev-parse --short HEAD'.
            out: 3111ba8
        hash: 3111ba8
            Check metadata tree in '/var/tmp/tmt/run-007/plans/sanity/discover/default/tests/'.
        summary: 2 tests selected
            /tests/commands/request
            /tests/commands/version
        status: done
        Write file '/var/tmp/tmt/run-007/plans/sanity/discover/step.yaml'.
        Write file '/var/tmp/tmt/run-007/plans/sanity/discover/tests.yaml'.
        Write file '/var/tmp/tmt/run-007/plans/sanity/discover/run.yaml'.
    provision
        workdir: /var/tmp/tmt/run-007/plans/sanity/provision
        how: container
        order: 50
        image: quay.io/testing-farm/cli:latest
            Check for container image 'quay.io/testing-farm/cli:latest'.
            out: 082f27d79382
        name: tmt-var-tmp-tmt-run-007-plans-sanity
            Start container 'quay.io/testing-farm/cli:latest'.
            Run command 'podman run --security-opt seccomp=unconfined --name tmt-var-tmp-tmt-run-007-plans-sanity -v /var/tmp/tmt/run-007/plans/sanity:/var/tmp/tmt/run-007/plans/sanity:Z -itd quay.io/testing-farm/cli:latest'.
            err: time="2022-02-09T20:46:01+01:00" level=warning msg="The input device is not a TTY. The --tty and --interactive flags might not work properly"
            out: 0de66e9ef36b875974b0b3e7a92e8f702af38b1c827438351643f9f352f651d9
            Run command 'podman exec tmt-var-tmp-tmt-run-007-plans-sanity sh -c cat /etc/os-release'.
            out: PRETTY_NAME="Debian GNU/Linux 11 (bullseye)"
            out: NAME="Debian GNU/Linux"
            out: VERSION_ID="11"
            out: VERSION="11 (bullseye)"
            out: VERSION_CODENAME=bullseye
            out: ID=debian
            out: HOME_URL="https://www.debian.org/"
            out: SUPPORT_URL="https://www.debian.org/support"
            out: BUG_REPORT_URL="https://bugs.debian.org/"
        distro: Debian GNU/Linux 11 (bullseye)
            Run command 'podman exec tmt-var-tmp-tmt-run-007-plans-sanity sh -c uname -r'.
            out: 5.15.16-100.fc34.x86_64
        kernel: 5.15.16-100.fc34.x86_64
        summary: 1 guest provisioned
        status: done
        Write file '/var/tmp/tmt/run-007/plans/sanity/provision/step.yaml'.
        Write file '/var/tmp/tmt/run-007/plans/sanity/provision/guests.yaml'.
    prepare
        workdir: /var/tmp/tmt/run-007/plans/sanity/prepare
        summary: 0 preparations applied
        status: done
        Write file '/var/tmp/tmt/run-007/plans/sanity/prepare/step.yaml'.
    execute
        workdir: /var/tmp/tmt/run-007/plans/sanity/execute
        how: tmt
        order: 50
        exit-first: False
            Write file '/var/tmp/tmt/run-007/plans/sanity/execute/data/tests/commands/request/metadata.yaml'.
            Write file '/var/tmp/tmt/run-007/plans/sanity/execute/data/tests/commands/version/metadata.yaml'.
        Write file '/var/tmp/tmt/run-007/plans/sanity/execute/tmt-file-submit'.
            Back up '/usr/bin/rstrnt-reboot' if present.
            Run command 'podman exec tmt-var-tmp-tmt-run-007-plans-sanity sh -c [ ! -e "/usr/bin/rstrnt-reboot" ]'.
            Run command 'podman exec tmt-var-tmp-tmt-run-007-plans-sanity sh -c cp "/var/tmp/tmt/run-007/plans/sanity/execute/default/reboot_template" "/usr/bin/rstrnt-reboot" && chmod +x "/usr/bin/rstrnt-reboot"'.
            err: Error: can only create exec sessions on running containers: container state improper
            Command returned '255'.
            Remove our reboot script implementations.
            Run command 'podman exec tmt-var-tmp-tmt-run-007-plans-sanity sh -c rm "/usr/bin/rstrnt-reboot"'.
            err: Error: can only create exec sessions on running containers: container state improper
            Command returned '255'.
    finish
        workdir: /var/tmp/tmt/run-007/plans/sanity/finish
            Run command 'podman container stop tmt-var-tmp-tmt-run-007-plans-sanity'.
            out: tmt-var-tmp-tmt-run-007-plans-sanity
        container: stopped
            Run command 'podman container rm -f tmt-var-tmp-tmt-run-007-plans-sanity'.
            out: 0de66e9ef36b875974b0b3e7a92e8f702af38b1c827438351643f9f352f651d9
        container: removed
        summary: 0 tasks completed
        status: done
        Write file '/var/tmp/tmt/run-007/plans/sanity/finish/step.yaml'.

stderr (1/1 lines)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Error: can only create exec sessions on running containers: container state improper

Failed to run command 'podman exec tmt-var-tmp-tmt-run-007-plans-sanity sh -c rm "/usr/bin/rstrnt-reboot"'. Reason: Command returned '255'.

I believe we should support setting entrypoint in these cases or maybe even force entrypoint to sh? WDYT @lukaszachy @psss ?