feat: duration from record (#15600)

Closes #15543

# Description

1. Simplify code in ``datetime.rs`` based on a suggestion in my last PR
on "datetime from record"
1. Make ``into duration`` work with durations inside a record, provided
as a cell path
1. Make ``into duration`` work with durations as record

# User-Facing Changes

```nushell
# Happy paths
~> {d: '1hr'} | into duration d
╭───┬─────╮
│ d │ 1hr │
╰───┴─────╯

~> {week: 10, day: 2, sign: '+'} | into duration
10wk 2day

# Error paths and invalid usage
~> {week: 10, day: 2, sign: 'x'} | into duration
Error: nu:🐚:incorrect_value

  × Incorrect value.
   ╭─[entry #4:1:26]
 1 │ {week: 10, day: 2, sign: 'x'} | into duration
   ·                          ─┬─    ──────┬──────
   ·                           │           ╰── encountered here
   ·                           ╰── Invalid sign. Allowed signs are +, -
   ╰────

~> {week: 10, day: -2, sign: '+'} | into duration
Error: nu:🐚:incorrect_value

  × Incorrect value.
   ╭─[entry #5:1:17]
 1 │ {week: 10, day: -2, sign: '+'} | into duration
   ·                 ─┬               ──────┬──────
   ·                  │                     ╰── encountered here
   ·                  ╰── number should be positive
   ╰────

~> {week: 10, day: '2', sign: '+'} | into duration
Error: nu:🐚:only_supports_this_input_type

  × Input type not supported.
   ╭─[entry #6:1:17]
 1 │ {week: 10, day: '2', sign: '+'} | into duration
   ·                 ─┬─               ──────┬──────
   ·                  │                      ╰── only int input data is supported
   ·                  ╰── input type: string
   ╰────

~> {week: 10, unknown: 1} | into duration
Error: nu:🐚:unsupported_input

  × Unsupported input
   ╭─[entry #7:1:1]
 1 │ {week: 10, unknown: 1} | into duration
   · ───────────┬──────────   ──────┬──────
   ·            │                   ╰── Column 'unknown' is not valid for a structured duration. Allowed columns are: week, day, hour, minute, second, millisecond, microsecond, nanosecond, sign
   ·            ╰── value originates from here
   ╰────

~> {week: 10, day: 2, sign: '+'} | into duration --unit sec
Error: nu:🐚:incompatible_parameters

  × Incompatible parameters.
   ╭─[entry #2:1:33]
 1 │ {week: 10, day: 2, sign: '+'} | into duration --unit sec
   ·                                 ──────┬────── ─────┬────
   ·                                       │            ╰── the units should be included in the record
   ·                                       ╰── got a record as input
   ╰────
```

# Tests + Formatting
- Add examples and integration tests for ``into duration``
- Add one test for ``into duration``

# After Submitting
If this is merged in time, I'll update my PR on the "datetime handling
highlights" for the release notes.

crates/nu-command/tests/commands/into_datetime.rs

@@ -2,6 +2,13 @@ use nu_test_support::nu;
 
 // Tests happy paths
 
+#[test]
+fn into_datetime_from_record_cell_path() {
+    let actual = nu!(r#"{d: '2021'} | into datetime d"#);
+
+    assert!(actual.out.contains("years ago"));
+}
+
 #[test]
 fn into_datetime_from_record() {
     let actual = nu!(

crates/nu-command/tests/commands/into_duration.rs

@@ -8,3 +8,103 @@ fn into_duration_float() {
 
     assert_eq!("1min 4sec 200ms", actual.out);
 }
+
+#[test]
+fn into_duration_from_record_cell_path() {
+    let actual = nu!(r#"{d: '1hr'} | into duration d"#);
+    let expected = nu!(r#"{d: 1hr}"#);
+
+    assert_eq!(expected.out, actual.out);
+}
+
+#[test]
+fn into_duration_from_record() {
+    let actual = nu!(
+        r#"{week: 10, day: 1, hour: 2, minute: 3, second: 4, millisecond: 5, microsecond: 6, nanosecond: 7, sign: '+'} | into duration | into record"#
+    );
+    let expected = nu!(
+        r#"{week: 10, day: 1, hour: 2, minute: 3, second: 4, millisecond: 5, microsecond: 6, nanosecond: 7, sign: '+'}"#
+    );
+
+    assert_eq!(expected.out, actual.out);
+}
+
+#[test]
+fn into_duration_from_record_negative() {
+    let actual = nu!(
+        r#"{week: 10, day: 1, hour: 2, minute: 3, second: 4, millisecond: 5, microsecond: 6, nanosecond: 7, sign: '-'} | into duration | into record"#
+    );
+    let expected = nu!(
+        r#"{week: 10, day: 1, hour: 2, minute: 3, second: 4, millisecond: 5, microsecond: 6, nanosecond: 7, sign: '-'}"#
+    );
+
+    assert_eq!(expected.out, actual.out);
+}
+
+#[test]
+fn into_duration_from_record_defaults() {
+    let actual = nu!(r#"{} | into duration | into int"#);
+
+    assert_eq!("0".to_string(), actual.out);
+}
+
+#[test]
+fn into_duration_from_record_round_trip() {
+    let actual = nu!(
+        r#"('10wk 1day 2hr 3min 4sec 5ms 6µs 7ns' | into duration | into record | into duration | into string) == '10wk 1day 2hr 3min 4sec 5ms 6µs 7ns'"#
+    );
+
+    assert!(actual.out.contains("true"));
+}
+
+#[test]
+fn into_duration_table_column() {
+    let actual =
+        nu!(r#"[[value]; ['1sec'] ['2min'] ['3hr'] ['4day'] ['5wk']] | into duration value"#);
+    let expected = nu!(r#"[[value]; [1sec] [2min] [3hr] [4day] [5wk]]"#);
+
+    assert_eq!(actual.out, expected.out);
+}
+
+// Tests error paths
+
+#[test]
+fn into_duration_from_record_fails_with_wrong_type() {
+    let actual = nu!(r#"{week: '10'} | into duration"#);
+
+    assert!(actual
+        .err
+        .contains("nu::shell::only_supports_this_input_type"));
+}
+
+#[test]
+fn into_duration_from_record_fails_with_invalid_date_time_values() {
+    let actual = nu!(r#"{week: -10} | into duration"#);
+
+    assert!(actual.err.contains("nu::shell::incorrect_value"));
+}
+
+#[test]
+fn into_duration_from_record_fails_with_invalid_sign() {
+    let actual = nu!(r#"{week: 10, sign: 'x'} | into duration"#);
+
+    assert!(actual.err.contains("nu::shell::incorrect_value"));
+}
+
+// Tests invalid usage
+
+#[test]
+fn into_duration_from_record_fails_with_unknown_key() {
+    let actual = nu!(r#"{week: 10, unknown: 1} | into duration"#);
+
+    assert!(actual.err.contains("nu::shell::unsupported_input"));
+}
+
+#[test]
+fn into_duration_from_record_incompatible_with_unit_flag() {
+    let actual = nu!(
+        r#"{week: 10, day: 1, hour: 2, minute: 3, second: 4, sign: '-'} | into duration --unit sec"#
+    );
+
+    assert!(actual.err.contains("nu::shell::incompatible_parameters"));
+}