wip: e2e in ci

script/e2e-container

@@ -0,0 +1,63 @@
+#!/bin/sh
+# script/e2e-container: run one command in a container with this repo at
+# /work, and exit with that command's status. Our own extension to
+# scripts-to-rule-them-all, used by script/test-e2e and
+# script/test-e2e-firefox.
+#
+# It takes the arguments you would give `docker run`, minus the mount and
+# the working directory:
+#
+#     script/e2e-container --ipc=host -e HOME=/tmp "$IMAGE" node foo.js
+#
+# It exists because `docker run -v "$ROOT:/work"` cannot work under Gitea
+# Actions. The runner executes the job inside a container and hands it the
+# host's docker socket, so the source side of a -v is resolved by the host
+# daemon and not inside the job. The job's checkout lives on a docker
+# volume mounted at /workspace, which is not a host path at all: measured
+# on this repo's runner, `docker run -v "$PWD:/work" ... ls -la /work`
+# listed an empty directory. A suite started that way dies with "Cannot
+# find module" rather than testing anything.
+#
+# So the repo is copied in rather than mounted. That is one mechanism for
+# CI and for a laptop instead of two, which matters more than the copy:
+# the path CI takes is the path a developer exercises on every local run.
+# The copy costs about two seconds for this tree, against a suite that
+# takes tens of seconds.
+#
+# Nothing is copied back out. Neither suite writes anything under the repo
+# — the browser profile and every temp file live under HOME, which both
+# callers point at /tmp inside the container.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+CID=""
+
+cleanup() {
+    if [ -n "$CID" ]; then
+        docker rm -f "$CID" >/dev/null 2>&1 || true
+    fi
+}
+
+main() {
+    if [ "$#" -eq 0 ]; then
+        echo "e2e-container: usage: e2e-container <docker-run-arg>..." >&2
+        exit 2
+    fi
+
+    cd "$ROOT"
+
+    CID="$(docker create -w /work "$@")"
+    trap cleanup EXIT
+    trap 'cleanup; exit 130' INT TERM
+
+    # `docker cp <dir> <cid>:/work` with /work absent creates it and
+    # copies the contents of <dir> into it. A failure here is fatal under
+    # set -e, so the command below can never run against an empty /work.
+    docker cp . "$CID:/work"
+
+    # --attach propagates the container's exit status.
+    docker start --attach "$CID"
+}
+
+main "$@"