How to assert part of a string

[wolframkriesing]

I would love to do something like this

tests:
  - name: ...
    stdout:
      contains: |
        12345

Currently, I had not found a way to assert for part of the string. In the docs I only saw how to match all of stdout.

PS: what is the | at the end of contains: |, is this yaml standard? You use it in many places but I didnt find an explanation. Thanks

[SamirTalwar]

That sounds like a pretty good proposal to me. I think we can do that.

What do you think the output should look like on a test failure? Currently we use git diff --no-index to produce something like:

name
  input:  12345
  stdout: @@ -1 +1 @@
          -12345
          +67890

Obviously a diff won't be useful when we're looking for a substring. Perhaps it would be appropriate to go back to the older style of Smoke output, with something like:

name
  input:  12345
  stdout:
    actual:
      this string contains the numbers 23456 and none other
    expected:
      contains:
        12345

What do you think?

[SamirTalwar]

EDIT: Turns out Smoke doesn't strip newlines. I was thinking of Smoke v1.0. I guess I fixed that.

FYI, | is part of standard YAML, and tells the YAML parser to parse all indented content as multiline text. So you could also use contains: "12345\n" if you wanted.

I find it useful when dealing with trailing newlines, large amounts of text, or if you want to avoid quoting text that might appear as some other datatype (e.g. null, true, 12345, etc.). For consistency, I tend to use it in all situations when writing Smoke tests.

These are all equivalent (tested with yq):

stuff:
  contents: |
    this paragraph is
    made up of multiple lines
    also a haiku

and:

stuff:
  contents: "this paragraph is\nmade up of multiple lines\nalso a haiku\n"

and also:

{
  "stuff": {
    "contents": "this paragraph is\nmade up of multiple lines\nalso a haiku\n"
  }
}