notescraft/crates/canvas/tests/robustness.rs

//! Malformed input, size caps and diagnostics: errors and diagnostics only, never a panic.

use notescraft_canvas::{Canvas, Color, Diagnostic, Error, MAX_BYTES, MAX_NODES};

fn err(input: &str) -> Error {
    match Canvas::from_str(input) {
        Ok(_) => panic!("expected an error for: {input}"),
        Err(e) => e,
    }
}

#[test]
fn truncated_json_is_an_error() {
    let path = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("tests/fixtures/truncated.canvas");
    let text = std::fs::read_to_string(&path).unwrap_or_else(|e| panic!("fixture: {e}"));
    assert!(matches!(err(&text), Error::Json(_)));
    assert!(matches!(err("{\"nodes\": ["), Error::Json(_)));
    assert!(matches!(err(""), Error::Json(_)));
}

#[test]
fn root_must_be_an_object() {
    assert!(matches!(err("[]"), Error::NotAnObject { .. }));
    assert!(matches!(err("\"canvas\""), Error::NotAnObject { .. }));
    assert!(matches!(err("42"), Error::NotAnObject { .. }));
}

#[test]
fn wrong_types_are_errors() {
    assert!(matches!(err("{\"nodes\": {}}"), Error::NotAnArray { .. }));
    assert!(matches!(err("{\"edges\": 3}"), Error::NotAnArray { .. }));
    assert!(matches!(err("{\"nodes\": [3]}"), Error::NotAnObject { .. }));
    assert!(matches!(err("{\"nodes\": [{\"id\": 3, \"type\": \"text\"}]}"), Error::BadType { .. }));
    assert!(matches!(err("{\"nodes\": [{\"type\": \"text\"}]}"), Error::MissingField { .. }));
    assert!(matches!(err("{\"nodes\": [{\"id\": \"a\"}]}"), Error::MissingField { .. }));
    assert!(matches!(err("{\"nodes\": [{\"id\": \"a\", \"type\": \"text\", \"x\": \"0\", \"y\": 0, \"width\": 1, \"height\": 1}]}"), Error::BadType { .. }));
    assert!(matches!(
        err("{\"nodes\": [{\"id\": \"a\", \"type\": \"text\", \"x\": 0, \"y\": 0, \"width\": 1, \"height\": 1, \"text\": 5}]}"),
        Error::BadType { .. }
    ));
    assert!(matches!(
        err("{\"nodes\": [{\"id\": \"a\", \"type\": \"text\", \"x\": 0, \"y\": 0, \"width\": 1, \"height\": 1, \"color\": 2}]}"),
        Error::BadType { .. }
    ));
    // unknown keys keep any value shape at all
    assert!(
        Canvas::from_str("{\"nodes\": [{\"id\": \"a\", \"type\": \"text\", \"x\": 0, \"y\": 0, \"width\": 1, \"height\": 1, \"unknown\": [\"a\", 2]}]}")
            .is_ok()
    );
    assert!(matches!(err("{\"edges\": [{\"id\": \"e\", \"fromNode\": \"a\"}]}"), Error::MissingField { .. }));
    assert!(matches!(err("{\"edges\": [{\"id\": \"e\", \"fromNode\": \"a\", \"toNode\": \"b\", \"fromSide\": \"up\"}]}"), Error::BadValue { .. }));
    assert!(matches!(err("{\"edges\": [{\"id\": \"e\", \"fromNode\": \"a\", \"toNode\": \"b\", \"toEnd\": \"triangle\"}]}"), Error::BadValue { .. }));
    assert!(matches!(
        err("{\"nodes\": [{\"id\": \"a\", \"type\": \"group\", \"x\": 0, \"y\": 0, \"width\": 1, \"height\": 1, \"backgroundStyle\": \"zoom\"}]}"),
        Error::BadValue { .. }
    ));
}

#[test]
fn bad_color_is_kept_and_flagged_not_rejected() {
    let c = Canvas::from_str(
        "{\"nodes\": [{\"id\": \"a\", \"type\": \"text\", \"text\": \"t\", \"x\": 0, \"y\": 0, \"width\": 1, \"height\": 1, \"color\": \"7\"}]}",
    )
    .expect("tolerant read");
    assert_eq!(c.nodes.first().map(|n| n.color.clone()), Some(Some(Color::Hex("7".into()))));
    assert!(matches!(c.validate().first(), Some(Diagnostic::BadColor { .. })));
}

#[test]
fn huge_numbers_are_diagnosed_or_rejected() {
    // serde_json rejects numbers that overflow f64.
    assert!(matches!(err("{\"nodes\": [{\"id\": \"a\", \"type\": \"text\", \"x\": 1e400, \"y\": 0, \"width\": 1, \"height\": 1}]}"), Error::Json(_)));
    // A finite but absurd coordinate is flagged, never rewritten.
    let c = Canvas::from_str("{\"nodes\": [{\"id\": \"a\", \"type\": \"text\", \"text\": \"t\", \"x\": 1e308, \"y\": -1e308, \"width\": 1, \"height\": 1}]}")
        .expect("parses");
    let diags = c.validate();
    assert_eq!(diags.len(), 2, "{diags:?}");
    assert!(diags.iter().all(|d| matches!(d, Diagnostic::AbsurdCoordinate { .. })));
    let again = Canvas::from_str(&c.to_string_pretty()).expect("re-parses");
    assert_eq!(c, again, "absurd coordinates are not rewritten");
}

#[test]
fn deep_nesting_is_rejected_not_overflowed() {
    let deep = format!("{}{}", "[".repeat(500), "]".repeat(500));
    assert!(matches!(err(&deep), Error::Json(_)));
}

#[test]
fn node_cap_is_enforced() {
    let ok = gen_nodes(MAX_NODES);
    let c = Canvas::from_str(&ok).expect("cap size parses");
    assert_eq!(c.nodes.len(), MAX_NODES);

    let too_many = gen_nodes(MAX_NODES + 1);
    assert!(matches!(err(&too_many), Error::TooManyNodes { .. }));
}

fn gen_nodes(count: usize) -> String {
    let mut s = String::from("{\"nodes\":[");
    for i in 0..count {
        if i > 0 {
            s.push(',');
        }
        s.push_str("{\"id\":\"n");
        s.push_str(&i.to_string());
        s.push_str("\",\"type\":\"text\",\"text\":\"\",\"x\":0,\"y\":0,\"width\":1,\"height\":1}");
    }
    s.push_str("]}");
    s
}

#[test]
fn size_cap_is_enforced() {
    let padding = "a".repeat(MAX_BYTES + 16);
    let big = format!("{{\"nodes\":[],\"edges\":[],\"x\":\"{padding}\"}}");
    assert!(big.len() > MAX_BYTES);
    assert!(matches!(err(&big), Error::TooLarge { .. }));
}