Example script that tests if migrations added in current working tree will break tests when applied to master. Good for PRs but can be used locally "safely"

test-migrations.sh

#! /bin/bash

# Assumes migrations are stored in ./db/migrations as single files.
# Also assumes migrations are in (alphanumeric) order.

set -e

rm -rf /tmp/test-migrations
mkdir /tmp/test-migrations
cp -r db/migrations/* /tmp/test-migrations/

git add .
git stash

git fetch origin master
git checkout master

git pull

NEW_MIGRATIONS=$(comm -23 <(ls /tmp/test-migrations | sort) <(ls db/migrations | sort))

IFS=$'\n';
for i in $NEW_MIGRATIONS; do
  echo "Testing with migration $i"
  cp /tmp/test-migrations/$i db/migrations
  make test
done;

git reset --hard master
git clean -fd

git checkout -

git stash pop || true