Incorrect `assert_data_eq` report

[smoelius]

Recently, I ran into a failure like this:¹

fn main() {
    let actual = r#"    before_tokens: "["let", "(", "_", ",", "ref_count"]","#;
    let expected = r#"    before_tokens: "[..]","#;
    snapbox::assert_data_eq!(actual, expected);
}

From what I can tell, the problem is:

• expected gets broken up into sections before_tokens: " and ",.
• The latter appears in the middle of actual just after let.
• When there are no more sections to process, line_matches returns false because remainder is not empty:

  snapbox/crates/snapbox/src/filter/pattern.rs

  Line 599 in 90fd7f0

  return remainder.is_empty();

Does that sound about right?

If so, would you be open to a reimplementation of line_matches that uses regex Captures?

Footnotes

1. Corrected per @Muscraft's comment: https://github.com/assert-rs/snapbox/issues/411#issuecomment-3539740339 ↩

[Muscraft]

I might be mistaken, but I think you have actual and expected swapped in your example.

When I swapped them and added square brackets around the wildcard, it passed:

fn main() {
    let actual = r#"    before_tokens: "["let", "(", "_", ",", "ref_count"]","#;
    let expected = r#"    before_tokens: "[[..]]","#;
    snapbox::assert_data_eq!(actual, expected);
}

---

If so, would you be open to a reimplementation of line_matches that uses regex Captures?

If you are looking to use regexs Redactions support them.

[smoelius]

I might be mistaken, but I think you have actual and expected swapped in your example.

Thanks. You are right. I've updated the example, but please let me know if it still looks messed up.

When I...added square brackets around the wildcard, it passed:

As you are likely aware, ", (the section after the [..]) appears in actual, but ]", does not.

(I wish it had occurred to me to try this.)

If you are looking to use regexs Redactions support them.

Are you suggesting that, rather that put [..] in expected, match the text with a Redaction?

[epage]

It sounds like we do a non-greedy match while you are wanting a greedy match. I am not too inclined to change to a greedy match at this time though we could keep this open for seeing what other attention we get on this in case we want a way to support both.

A key part of the design for this is that the syntax be readable outside of tests. For example, we use these redactions in clap documentation (through trycmd).

[smoelius]

@Muscraft's observation regarding the brackets provides a workaround, so I no longer have an immediate need for a fix.

A key part of the design for this is that the syntax be readable outside of tests. For example, we use these redactions in clap documentation (through trycmd).

👍