nushell/crates/nu-command/tests/commands/skip/skip_.rs
Devyn Cairns c61075e20e
Add string/binary type color to ByteStream (#12897)
# Description

This PR allows byte streams to optionally be colored as being
specifically binary or string data, which guarantees that they'll be
converted to `Binary` or `String` appropriately on `into_value()`,
making them compatible with `Type` guarantees. This makes them
significantly more broadly usable for command input and output.

There is still an `Unknown` type for byte streams coming from external
commands, which uses the same behavior as we previously did where it's a
string if it's UTF-8.

A small number of commands were updated to take advantage of this, just
to prove the point. I will be adding more after this merges.

# User-Facing Changes
- New types in `describe`: `string (stream)`, `binary (stream)`
- These commands now return a stream if their input was a stream:
  - `into binary`
  - `into string`
  - `bytes collect`
  - `str join`
  - `first` (binary)
  - `last` (binary)
  - `take` (binary)
  - `skip` (binary)
- Streams that are explicitly binary colored will print as a streaming
hexdump
  - example:
    ```nushell
    1.. | each { into binary } | bytes collect
    ```

# Tests + Formatting
I've added some tests to cover it at a basic level, and it doesn't break
anything existing, but I do think more would be nice. Some of those will
come when I modify more commands to stream.

# After Submitting
There are a few things I'm not quite satisfied with:

- **String trimming behavior.** We automatically trim newlines from
streams from external commands, but I don't think we should do this with
internal commands. If I call a command that happens to turn my string
into a stream, I don't want the newline to suddenly disappear. I changed
this to specifically do it only on `Child` and `File`, but I don't know
if this is quite right, and maybe we should bring back the old flag for
`trim_end_newline`
- **Known binary always resulting in a hexdump.** It would be nice to
have a `print --raw`, so that we can put binary data on stdout
explicitly if we want to. This PR doesn't change how external commands
work though - they still dump straight to stdout.

Otherwise, here's the normal checklist:

- [ ] release notes
- [ ] docs update for plugin protocol changes (added `type` field)

---------

Co-authored-by: Ian Manske <ian.manske@pm.me>
2024-05-20 00:35:32 +00:00

23 lines
468 B
Rust

use nu_test_support::nu;
#[test]
fn skips_bytes() {
let actual = nu!("(0x[aa bb cc] | skip 2) == 0x[cc]");
assert_eq!(actual.out, "true");
}
#[test]
fn skips_bytes_from_stream() {
let actual = nu!("([0 1] | each { 0x[aa bb cc] } | bytes collect | skip 2) == 0x[cc aa bb cc]");
assert_eq!(actual.out, "true");
}
#[test]
fn fail_on_non_iterator() {
let actual = nu!("1 | skip 2");
assert!(actual.err.contains("command doesn't support"));
}