Add tests for new config

Author: mcncl

README.md

@@ -55,6 +55,14 @@ Which shell check image to use.
 
 Default: `koalaman/shellcheck`
 
+## Developing
+
+To run the tests:
+
+```bash
+docker-compose run --rm tests bats tests
+```
+
 ## License
 
 MIT (see [LICENSE](LICENSE))

compose.yml

@@ -0,0 +1,5 @@
+services:
+  tests:
+    image: buildkite/plugin-tester:v4.1.1
+    volumes:
+      - ".:/plugin"

tests/run.bats

@@ -189,3 +189,39 @@ load "${BATS_PLUGIN_PATH}/load.bash"
 
   unstub docker
 }
+
+@test "Shellcheck uses default image when not specified" {
+  export BUILDKITE_PLUGIN_SHELLCHECK_FILES_0="tests/testdata/test.sh"
+  unset BUILDKITE_PLUGIN_SHELLCHECK_IMAGE
+  unset BUILDKITE_PLUGIN_SHELLCHECK_VERSION
+
+  stub docker \
+    "run --rm -v $PWD:/mnt --workdir /mnt koalaman/shellcheck:stable --color=always tests/testdata/test.sh : echo running shellcheck on test.sh"
+
+  run "$PWD/hooks/command"
+
+  assert_success
+  assert_output --partial "Running shellcheck on 1 files"
+  assert_output --partial "running shellcheck on test.sh"
+  assert_output --partial "Files are ok"
+
+  unstub docker
+}
+
+@test "Shellcheck uses default image when specified" {
+  export BUILDKITE_PLUGIN_SHELLCHECK_FILES_0="tests/testdata/test.sh"
+  export BUILDKITE_PLUGIN_SHELLCHECK_IMAGE="foo/shellcheck"
+  export BUILDKITE_PLUGIN_SHELLCHECK_VERSION="bar"
+
+  stub docker \
+    "run --rm -v $PWD:/mnt --workdir /mnt foo/shellcheck:bar --color=always tests/testdata/test.sh : echo running shellcheck on test.sh"
+
+  run "$PWD/hooks/command"
+
+  assert_success
+  assert_output --partial "Running shellcheck on 1 files"
+  assert_output --partial "running shellcheck on test.sh"
+  assert_output --partial "Files are ok"
+
+  unstub docker
+}