Support container provisioner in toolbox

For Fedora Silverblue users it is common to run podman
via `flatpak-spawn --host` which runs podman on the host
system itself. This requires to pass the toolbox container
name when running `podman cp` to correctly copy stuff
from the toolbox container, where `tmt` is installed
to the provisioned container.

Fixes #1020

Signed-off-by: Miroslav Vadkerti <mvadkert@redhat.com>

tests/provision/container/toolbox/main.fmf

@@ -0,0 +1,7 @@
+summary: Test container provisioner in toolbox
+description:
+    Make sure that container provisioner works well
+    in a toolbox container.
+tag+:
+    - provision-only
+    - provision-container

tests/provision/container/toolbox/podman_wrapper

@@ -0,0 +1,2 @@
+#!/bin/bash
+flatpak-spawn --host podman "$@"

tests/provision/container/toolbox/test.sh

@@ -0,0 +1,48 @@
+#!/bin/bash
+. /usr/share/beakerlib/beakerlib.sh || exit 1
+
+rlJournalStart
+    rlPhaseStartSetup
+        rlRun "toolbox_container_name=\$(uuidgen)" 0 "Generate toolbox container name"
+    rlPhaseEnd
+
+    rlPhaseStartTest "Create toolbox container"
+	rlRun "toolbox create -y $toolbox_container_name"
+    rlPhaseEnd
+
+    toolbox_run() {
+      toolbox run --container "$toolbox_container_name" "$@"
+    }
+
+    if env | grep -q PACKIT_COPR_PROJECT; then
+	rlPhaseStartTest "Install tmt in from copr repository"
+	    TMT_COMMAND="tmt"
+	    rlRun "toolbox_run dnf -y install dnf-plugins-core"
+	    rlRun "toolbox_run dnf -y copr enable $PACKIT_COPR_PROJECT"
+	    rlRun "toolbox_run dnf -y install tmt-provision-container"
+	rlPhaseEnd
+    else
+	rlPhaseStartTest "Install hatch, expecting local execution"
+	    TMT_COMMAND="hatch run dev:tmt"
+	    rlRun "toolbox_run dnf -y install hatch"
+	rlPhaseEnd
+    fi
+
+    rlPhaseStartTest "Print tmt version installed in toolbox"
+	rlRun "toolbox_run $TMT_COMMAND --version"
+    rlPhaseEnd
+
+    rlPhaseStartTest "Add podman wrapper"
+	rlRun "podman cp podman_wrapper $toolbox_container_name:/usr/bin/podman"
+	rlRun "toolbox_run podman --version"
+    rlPhaseEnd
+
+    rlPhaseStartTest "Verify container provisioner works from toolbox"
+	rlRun -s "toolbox_run tmt run -a -vvv provision -h container execute -h tmt -s 'echo hello from container'"
+	rlAssertGrep "content: hello from container" $rlRun_LOG
+    rlPhaseEnd
+
+    rlPhaseStartCleanup
+        rlRun "toolbox rm -f $toolbox_container_name" 0 "Remove toolbox container"
+    rlPhaseEnd
+rlJournalEnd

tmt/steps/provision/podman.py

@@ -1,4 +1,5 @@
 import dataclasses
+import functools
 import os
 from shlex import quote
 from typing import Any, Optional, Union, cast
@@ -283,6 +284,33 @@ def _run_ansible(
             log=log,
             silent=silent)
 
+    @functools.cached_property
+    def _is_toolbox(self) -> bool:
+        """ Return ``True`` if running in toolbox, ``False`` otherwise. """
+        if os.path.exists('/run/.toolboxenv'):
+            return True
+
+        return False
+
+    @functools.cached_property
+    def _toolbox_container_name(self) -> Optional[str]:
+        """ Returns toolbox container name if running in toolbox, ``None`` otherwise. """
+        if not self._is_toolbox:
+            return None
+
+        if not os.path.exists('/run/.containerenv'):
+            self.logger.warning(
+                "Unable to detect toolbox container name, '/run/.containerenv' not found."
+                )
+            return None
+
+        with open('/run/.containerenv') as envfile:
+            for line in envfile.readline():
+                if line.startswith('name="'):
+                    return line[6:-1]
+
+        return None
+
     def podman(
             self,
             command: Command,
@@ -376,10 +404,19 @@ def push(
             self._run_guest_command(Command(
                 "chcon", "--recursive", "--type=container_file_t", self.parent.plan.workdir
                 ), shell=False, silent=True)
+
         # In case explicit destination is given, use `podman cp` to copy data
-        # to the container
+        # to the container. If running in toolbox, make sure to copy from the toolbox
+        # container instead of localhost.
         if source and destination:
-            self.podman(Command("cp", source, f"{self.container}:{destination}"))
+            self.podman(
+                Command(
+                    "cp",
+                    f"{self._toolbox_container_name}:{source}"
+                    if self._toolbox_container_name else source,
+                    f"{self.container}:{destination}"
+                    )
+                )
 
     def pull(
             self,