Expose a diffing iterator

[epage]

Some example use cases

• Report more detailed information than is_different
  • first diff
  • all diffs
  • all regular and diffs
• Custom content comparisons
  • line-ending agnostic
  • Using the difference crate

You can look at the implementation of is_different to see how simple it is. I have a test branch of cobalt that replaces the custom directory diffing with this, augmented to use difference:

fn assert_dirs_eq(expected: &Path, actual: &Path) {
     for entry in dir_diff::DirDiff::new(expected, actual) {
        let entry = entry
            .unwrap()
            .assert_exists()
            .and_then(dir_diff::DiffEntry::assert_file_type)
            .and_then(assert_content);
        if let Err(error) = entry {
            panic!("{}", error);
        }
      }
  }

Controversial API choices

• Prefixing the test functions with assert despite them erroring rather than panicing. I wasn't sure of a better name

Potential areas for the API to expand

• Make it even easier to get the first or all differences
• Make it easier to have a nice panic

Potential areas for chrome improvement

• AssertionError's Display
• Have a fancy feature that uses difference
  • Limit on file size?
  • Assume anything convertable to String / UTF-8 is text?
  • Use a extension crate to detect text?
  • Use a content sniffer to detect text?

[epage]

@steveklabnik This is a big change. Is it something you're wanting to look at before I submit?

[epage]

These asserts are a it of a pain to work with. Until the other day, I didn't know you could have more complex selfs.

This might be a way to improve things.