dendron 0.1.4

Generic tree data structure
Documentation 
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//! Tests for pretty debug printing.

use core::fmt;

use dendron::{tree_node, Node};

#[derive(Clone)]
struct Label(Vec<i32>);

impl fmt::Debug for Label {
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // Use `Vec<i32>`'s debug formatting.
        self.0.fmt(f)
    }
}

impl fmt::Display for Label {
    // `1/2/3` for normal formatting, and `1 -> 2 -> 3` for alternate formatting.
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let mut iter = self.0.iter();
        match iter.next() {
            Some(v) => write!(f, "{v}")?,
            None => return write!(f, "root"),
        }
        if f.alternate() {
            iter.try_for_each(|v| write!(f, " -> {v}"))
        } else {
            iter.try_for_each(|v| write!(f, "/{v}"))
        }
    }
}

macro_rules! label {
    ($($tt:tt)*) => {
        Label(vec![$($tt)*])
    }
}

fn sample_tree() -> Node<Label> {
    //  []
    //  |-- [0]
    //  |-- [1]
    //  |   |-- [1, 0]
    //  |   |   `-- [1, 0, 0]
    //  |   |-- [1, 1]
    //  |   `-- [1, 2]
    //  |       `-- [1, 2, 0]
    //  `-- [2]
    //      |-- [2, 0]
    //      |   `-- [2, 0, 0]
    //      `-- [2, 1]
    //          `-- [2, 1, 0]
    tree_node! {
        label![], [
            label![0],
            /(label![1], [
                /(label![1, 0], [
                    label![1, 0, 0],
                ]),
                label![1, 1],
                /(label![1, 2], [
                    label![1, 2, 0],
                ]),
            ]),
            /(label![2], [
                /(label![2, 0], [
                    label![2, 0, 0],
                ]),
                /(label![2, 1], [
                    label![2, 1, 0],
                ]),
            ]),
        ]
    }
}

#[test]
fn debug() {
    const EXPECTED: &str = r#"[]
|-- [0]
|-- [1]
|   |-- [1, 0]
|   |   `-- [1, 0, 0]
|   |-- [1, 1]
|   `-- [1, 2]
|       `-- [1, 2, 0]
`-- [2]
    |-- [2, 0]
    |   `-- [2, 0, 0]
    `-- [2, 1]
        `-- [2, 1, 0]"#;

    assert_eq!(
        format!("{:?}", sample_tree().debug_pretty_print()),
        EXPECTED
    );
}

#[test]
fn debug_alternate() {
    const EXPECTED: &str = r#"[]
|-- [
|       0,
|   ]
|-- [
|       1,
|   ]
|   |-- [
|   |       1,
|   |       0,
|   |   ]
|   |   `-- [
|   |           1,
|   |           0,
|   |           0,
|   |       ]
|   |-- [
|   |       1,
|   |       1,
|   |   ]
|   `-- [
|           1,
|           2,
|       ]
|       `-- [
|               1,
|               2,
|               0,
|           ]
`-- [
        2,
    ]
    |-- [
    |       2,
    |       0,
    |   ]
    |   `-- [
    |           2,
    |           0,
    |           0,
    |       ]
    `-- [
            2,
            1,
        ]
        `-- [
                2,
                1,
                0,
            ]"#;

    assert_eq!(
        format!("{:#?}", sample_tree().debug_pretty_print()),
        EXPECTED
    );
}

#[test]
fn display() {
    const EXPECTED: &str = r#"root
|-- 0
|-- 1
|   |-- 1/0
|   |   `-- 1/0/0
|   |-- 1/1
|   `-- 1/2
|       `-- 1/2/0
`-- 2
    |-- 2/0
    |   `-- 2/0/0
    `-- 2/1
        `-- 2/1/0"#;

    assert_eq!(format!("{}", sample_tree().debug_pretty_print()), EXPECTED);
}

#[test]
fn display_alternate() {
    const EXPECTED: &str = r#"root
|-- 0
|-- 1
|   |-- 1 -> 0
|   |   `-- 1 -> 0 -> 0
|   |-- 1 -> 1
|   `-- 1 -> 2
|       `-- 1 -> 2 -> 0
`-- 2
    |-- 2 -> 0
    |   `-- 2 -> 0 -> 0
    `-- 2 -> 1
        `-- 2 -> 1 -> 0"#;

    assert_eq!(
        format!("{:#}", sample_tree().debug_pretty_print()),
        EXPECTED
    );
}