Testing

Dalec supports adding tests to your spec file. These tests are run against the container produced by your spec. Dalec provides a few test helpers to make it easier to write tests when your image doesn’t have the tools you need.

Checks for files

Check file existence

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    files:
      /usr/bin/foo:

Check file contents

Here are some examples on how to check the contents and metadata of a file in the output container. You can use these to check that the files you expect are present and have the correct contents.

Check that a file contains some value:

Here we check that the content of the file /etc/foo.conf contains the string foo=bar. You can specify multiple values to check for.

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    files:
      /etc/foo.conf:
        contains:
          - foo=bar

Check that a file starts with some value:

Here we check that the content of the file /etc/foo.conf starts with the string foo.

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    files:
      /etc/foo.conf:
        starts_with: foo

Check that a file ends with some value:

Here we check that the content of the file /etc/foo.conf ends with the string bar.

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    files:
      /etc/foo.conf:
        ends_with: bar

Check that a file matches a regular expression:

Here we check that the content of the file /etc/foo.conf matches one of the regular expressions (in this case only foo=.*).

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    files:
      /etc/foo.conf:
        matches: 
          - "foo=.*"

Check that a file does not exist

Here we check that the file /some/nonexistent/path does not exist.

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    files:
      /some/nonexistent/path:
        not_exist: true

Check that a path is a directory

Here we check that the path /some/path is a directory.

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    files:
      /some/path:
        is_dir: true

Check file permissions

Here we check that the file /etc/foo.conf has the permissions 0644.

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    files:
      /etc/foo.conf:
        contains:
          - foo=bar
        starts_with: foo
        ends_with: bar
        matches: 
          - "foo=.*"
        permissions: 0644

Add multiple checks together

You can add multiple checks together to check multiple things about a file. Note that some checks are mutually exclusive and will cause an error if you try to use them together.

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    files:
      /etc/foo.conf:
        contains:
          - foo=bar
        starts_with: foo
        ends_with: bar
        matches: 
          - "foo=.*"
        permissions: 0644

Symlinks

To check the target of a symlink set the link_target field:

tests:
  - name: My Test case
    files:
      /some/path:
        link_target: /expected/target

Run a command

You can run a command in the container and check the stdout and/or stderr of that command. These commands are run before any of the file checks are run and may influence the output of those checks.

Because these images often will not have a shell in them, if you want a shell you’ll need to run it explicitly.

Capture stdio streams

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    steps:
      - command: echo "hello world"
        stdout:
          equals:
            - hello world\n
      - # Note: the image used for this test would need to have a shell in it for this to work
        command: /bin/sh -c 'echo "hello world" >&2'
        stderr:
          equals:
            - hello world\n

Pass in stdin to the command:

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    steps:
      - command: cat
        stdin: hello world
        stdout:
          equals:
            - hello world

Inject a file into the container for additional checks

Test cases support source mounts just like in the main spec. You can use this to inject files, build helper binaries, or add whatever you need to run a test.

name: My Package
# ... other spec fields

tests:
  - name: My Test case
    mounts:
      - dest: /target/mount/path
        spec:
          build:
            source:
              inline:
                file:
                  contents: |
                    FROM busybox
                    RUN echo hello > /hello

                    FROM scratch
                    COPY --from=busybox /hello /hello
    steps:
      - command: cat /path/in/container
        stdout:
          equals: hello