nushell/crates/nu-command/tests/commands/reduce.rs

use nu_test_support::{nu, pipeline};

#[test]
fn reduce_table_column() {
    let actual = nu!(
        cwd: ".", pipeline(
        r#"
        echo "[{month:2,total:30}, {month:3,total:10}, {month:4,total:3}, {month:5,total:60}]"
        | from json
        | get total
        | reduce -f 20 { = $it + $( math eval `{{$acc}}^1.05` )}
        | str from -d 1
        "#
        )
    );

    assert_eq!(actual.out, "180.6");

    let actual = nu!(
        cwd: ".", pipeline(
        r#"
        echo "[{month:2,total:30}, {month:3,total:10}, {month:4,total:3}, {month:5,total:60}]"
        | from json
        | reduce -f 20 { = $it.total + $( math eval `{{$acc}}^1.05` )}
        | str from -d 1
        "#
        )
    );

    assert_eq!(actual.out, "180.6");
}

#[test]
fn reduce_rows_example() {
    let actual = nu!(
        cwd: ".", pipeline(
        r#"
        echo a,b 1,2 3,4
        | split column ,
        | headers
        | reduce -f 1.6 { = $acc * $(echo $it.a | str to-int) + $(echo $it.b | str to-int) }
        "#
        )
    );

    assert_eq!(actual.out, "14.8");
}

#[test]
fn reduce_numbered_example() {
    let actual = nu!(
        cwd: ".", pipeline(
        r#"
        echo one longest three bar
        | reduce -n { if $(echo $it.item | str length) > $(echo $acc.item | str length) {echo $it} {echo $acc}}
        | get index
        "#
        )
    );

    assert_eq!(actual.out, "1");
}

#[test]
fn folding_with_tables() {
    let actual = nu!(
        cwd: ".", pipeline(
        r#"
        echo [10 20 30 40]
        | reduce -f [] {
            with-env [value $it] {
              echo $acc | append $(= 10 * $(= $nu.env.value | str to-int))
            }
          }
        | math sum
        "#
        )
    );

    assert_eq!(actual.out, "1000");
}

#[test]
fn error_reduce_fold_type_mismatch() {
    let actual = nu!(
        cwd: ".", pipeline(
        r#"
        echo a b c | reduce -f 0 { = $acc + $it }
        "#
        )
    );

    assert!(actual.err.contains("Coercion"));
}

#[test]
fn error_reduce_empty() {
    let actual = nu!(
        cwd: ".", pipeline(
        r#"
        reduce { = $acc + $it }
        "#
        )
    );

    assert!(actual.err.contains("needs input"));
}