util: add bats-assert helper

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

.github/workflows/bats-assert.yml

@@ -0,0 +1,38 @@
+name: bats-assert
+
+on:
+  push:
+    branches:
+      - 'master'
+    paths:
+      - '.github/workflows/bats-assert.yml'
+      - 'util/bats-assert/**'
+  pull_request:
+    branches:
+      - 'master'
+    paths:
+      - '.github/workflows/bats-assert.yml'
+      - 'util/bats-assert/**'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: docker/setup-qemu-action@v1
+      - uses: docker/setup-buildx-action@v1
+      -
+        name: Test
+        working-directory: ./util/bats-assert
+        run: docker buildx bake test
+      -
+        name: Login to DockerHub
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v1.6.0
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      -
+        name: Publish
+        working-directory: ./util/bats-assert
+        run: docker buildx bake all --push

util/bats-assert/Dockerfile

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+FROM --platform=$BUILDPLATFORM alpine AS build
+RUN apk add --no-cache git
+WORKDIR /work
+RUN git clone --bare git://github.com/ztombol/bats-support && \
+    mkdir -p /out/bats-support && cd /out/bats-support && \
+    git --git-dir=/work/bats-support.git --work-tree=. checkout 004e707638eedd62e0481e8cdc9223ad471f12ee -- src load.bash LICENSE
+
+RUN git clone --bare git://github.com/ztombol/bats-assert && \
+    mkdir -p /out/bats-assert && cd /out/bats-assert && \
+    git --git-dir=/work/bats-assert.git --work-tree=. checkout 9f88b4207da750093baabc4e3f41bf68f0dd3630 -- src load.bash LICENSE
+
+RUN echo 'source "$(dirname "${BASH_SOURCE[0]}")/bats-support/load.bash"' > /out/assert.bash && \
+    echo 'source "$(dirname "${BASH_SOURCE[0]}")/bats-assert/load.bash"' >> /out/assert.bash
+
+
+FROM scratch AS release
+COPY --from=build /out /
+
+FROM alpine AS test-gen
+RUN apk add --no-cache bats
+WORKDIR /work
+COPY --from=release . .
+COPY test.bats .
+RUN bats ./test.bats &> test.bats.output || true
+
+FROM test-gen AS test
+COPY test.bats.golden .
+RUN diff test.bats.output test.bats.golden
+
+FROM scratch AS golden
+COPY --from=test-gen /work/test.bats.output test.bats.golden
+
+FROM release

util/bats-assert/docker-bake.hcl

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+variable "TARGET_REPO" {
+    default = "tonistiigi/bats-assert"
+}
+
+target "default" {
+    tags = ["${TARGET_REPO}"]
+    cache-to = ["type=inline"]
+    cache-from = ["${TARGET_REPO}"]
+}
+
+target "all" {
+    inherits = ["default"]
+    platforms = [
+        "linux/amd64",
+        "linux/arm64",
+        "linux/arm/v7",
+        "linux/arm/v6",
+        "linux/arm/v5",
+        "linux/386",
+        "linux/riscv64",
+        "linux/s390x",
+        "linux/ppc64le"
+    ]
+}
+
+target "test" {
+    target = "test"
+}
+
+target "generate-golden" {
+    target = "golden"
+    output = [
+        "."
+    ]
+}

util/bats-assert/test.bats

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+#!/usr/bin/env bats
+
+load 'assert'
+
+@test "failing" {
+  assert_equal "foo" "bar"
+}
+
+@test "run-no-success" {
+  run echo "start" && false
+  assert_failure
+}
+
+@test "run foobar" {
+  run ./foobar
+  assert_failure
+}
+
+@test "run" {
+  run echo "abc"
+  assert_success
+  assert_output "abc"
+}
+
+@test "run-fail" {
+  run echo "abc"
+  assert_success
+  assert_output "bcd"
+}

util/bats-assert/test.bats.golden

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+1..5
+not ok 1 failing
+# (from function `assert_equal' in file bats-assert/src/assert.bash, line 91,
+#  in test file test.bats, line 6)
+#   `assert_equal "foo" "bar"' failed
+# 
+# -- values do not equal --
+# expected : bar
+# actual   : foo
+# --
+# 
+not ok 2 run-no-success
+# (in test file test.bats, line 10)
+#   `run echo "start" && false' failed
+ok 3 run foobar
+ok 4 run
+not ok 5 run-fail
+# (from function `assert_output' in file bats-assert/src/assert.bash, line 239,
+#  in test file test.bats, line 28)
+#   `assert_output "bcd"' failed
+# 
+# -- output differs --
+# expected : bcd
+# actual   : abc
+# --
+#