nushell/crates/nu-command/tests/commands/first.rs
Ian Manske 56cdee1fd8
Refactor first and last (#12478)
# Description

- Refactors `first` and `last` using `Vec::truncate` and `Vec::drain`.
- `std::mem::take` was also used to eliminate a few `Value` clones.
- The `NeedsPositiveValue` error now uses the span of the `rows`
argument instead of the call head span.
- `last` now errors on an empty stream to match `first` which does
error.
-  Made metadata preservation more consistent.

# User-Facing Changes
Breaking change: `last` now errors on an empty stream to match `first`
which does error.
2024-04-13 14:58:54 +00:00

92 lines
2.2 KiB
Rust

use nu_test_support::fs::Stub::EmptyFile;
use nu_test_support::nu;
use nu_test_support::playground::Playground;
#[test]
fn gets_first_rows_by_amount() {
Playground::setup("first_test_1", |dirs, sandbox| {
sandbox.with_files(vec![
EmptyFile("los.txt"),
EmptyFile("tres.txt"),
EmptyFile("amigos.txt"),
EmptyFile("arepas.clu"),
]);
let actual = nu!(cwd: dirs.test(), "ls | first 3 | length");
assert_eq!(actual.out, "3");
})
}
#[test]
fn gets_all_rows_if_amount_higher_than_all_rows() {
Playground::setup("first_test_2", |dirs, sandbox| {
sandbox.with_files(vec![
EmptyFile("los.txt"),
EmptyFile("tres.txt"),
EmptyFile("amigos.txt"),
EmptyFile("arepas.clu"),
]);
let actual = nu!(
cwd: dirs.test(), "ls | first 99 | length");
assert_eq!(actual.out, "4");
})
}
#[test]
fn gets_first_row_when_no_amount_given() {
Playground::setup("first_test_3", |dirs, sandbox| {
sandbox.with_files(vec![EmptyFile("caballeros.txt"), EmptyFile("arepas.clu")]);
// FIXME: We should probably change first to return a one row table instead of a record here
let actual = nu!(cwd: dirs.test(), "ls | first | values | length");
assert_eq!(actual.out, "4");
})
}
#[test]
fn gets_first_row_as_list_when_amount_given() {
let actual = nu!("[1, 2, 3] | first 1 | describe");
assert_eq!(actual.out, "list<int>");
}
#[test]
fn gets_first_bytes() {
let actual = nu!("(0x[aa bb cc] | first 2) == 0x[aa bb]");
assert_eq!(actual.out, "true");
}
#[test]
fn gets_first_byte() {
let actual = nu!("0x[aa bb cc] | first");
assert_eq!(actual.out, "170");
}
#[test]
// covers a situation where `first` used to behave strangely on list<binary> input
fn works_with_binary_list() {
let actual = nu!("([0x[01 11]] | first) == 0x[01 11]");
assert_eq!(actual.out, "true");
}
#[test]
fn errors_on_negative_rows() {
let actual = nu!("[1, 2, 3] | first -10");
assert!(actual.err.contains("use a positive value"));
}
#[test]
fn errors_on_empty_list_when_no_rows_given() {
let actual = nu!("[] | first");
assert!(actual.err.contains("index too large"));
}