WIP: run buildah bud tests using podman

Set of scripts to run buildah's bud.bats test using
podman build in podman CI.

podman build is not 100% compatible with buildah bud.
In particular:

  * podman defaults to --layers=true; buildah to false
  * podman defaults to --force-rm=true; buildah to false
  * podman error exit status is 125; buildah is 2
  * differences in error messages, command-line arguments

Some of the above can be dealt with programmatically,
by tweaking the buildah helpers.bash (BATS helpers).
Some need to be tweaked by patching bud.bats itself.
This PR includes a patch that will, I fear, need to
be periodically maintained over time.

There will likely be failures when vendoring in a
new buildah, possibly because new tests were added
for new features that don't exist in podman, possibly
(I hope unlikely) if existing tests are changed in
ways that make the patch file fail to apply. I've
tried to write good instructions and to write the run
script in such a way that it will offer helpful hints
on failure. My instructions and code will be imperfect;
I hope they will be good enough to merit continued use
of this test (possibly with improvements to the instructions
as we learn more about real-world failures).

Signed-off-by: Ed Santiago <santiago@redhat.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/test/buildah-bud/make-new-buildah-diffs b/test/buildah-bud/make-new-buildah-diffs
new file mode 100644
index 000000000..1191f4597
--- /dev/null
+++ b/test/buildah-bud/make-new-buildah-diffs
@@ -0,0 +1,63 @@
+#!/bin/bash
+#
+# This script is intended to help developers get buildah-tests-under-podman
+# working again in case of failure.
+#
+ME=$(basename $0)
+
+die() {
+    echo "$ME: $*" >&2
+    exit 1
+}
+
+# Confirm that we're in a test-buildah* subdir of podman
+whereami=$(basename $(pwd))
+if [[ ! $whereami =~ test-buildah-v ]]; then
+    die "Please run me while cd'ed to a test-buildah-vN.M directory"
+fi
+
+# FIXME: check that git repo is buildah
+git remote -v | grep -q [BUILDAHREPO] \
+    || die "This does not look like a buildah repo (git remote -v)"
+
+# We could do the commit automatically, but it's prudent to require human
+# involvement.
+modified=$(git status --untracked=no --porcelain)
+if [[ -n "$modified" ]]; then
+    echo $modified
+    die "Please commit your changes: git commit --amend --all"
+fi
+
+# Remove any 00??-*.patch files
+rm -f 0001-*.patch
+
+# Check count of commits, barf if need to squash
+n_commits=$(git log --pretty=format:%h [BASETAG]..HEAD | wc -l)
+if [[ $n_commits -gt 1 ]]; then
+    die "Please squash your commits"
+fi
+
+# Scope check: make sure the only files changed are under tests/
+changes=$(git diff --name-status [BASETAG]..HEAD | egrep -v '\stests/')
+if [[ -n "$changes" ]]; then
+    echo $changes
+    die "Found modified files other than under 'tests/'"
+fi
+
+###############################################################################
+# All right - things look good. Generate the patch, and copy it into place.
+
+git format-patch [BASETAG]
+
+# Once again, make sure there's exactly one and only one commit
+shopt -s nullglob
+patch2=$(echo 0002-*.patch)
+if [[ -n "$patch2" ]]; then
+    die "Internal error: I thought I checked for squashed commits, but still see $patch2"
+fi
+
+# All looks good. Now write that patch into its proper place in the
+# podman repo. The sed and tac mess strips trailing whitespace and
+# empty lines; we need to do this to pass github CI checks.
+sed -e 's/ \+$//' <0001-*.patch |\
+    tac | sed -e '/./,$!d' | tac >| ../test/buildah-bud/buildah-tests.diff