iris/tests/unsettled.rs

//! The smallest tree that lays out differently on a second frame, shrunk from
//! a 402-widget one `tests/shrink.rs` grew. Both of these fail: a cold frame
//! leaves a wrapping text shaped at a width it was measured in rather than the
//! one it was given, and a repaint is what puts it right. So the warm-against-
//! cold oracle in `generated.rs` has been comparing against a tree that had
//! not settled, and some of what it called a warm defect is the cold side
//! being wrong.

use iris::harness::Harness;
use iris::prelude::*;

/// Six widgets, shrunk from a 402-widget tree the fuzzer found. Nothing about
/// the tree changes -- every widget is marked for redraw and the frame is
/// taken again -- so no box may move, and a warm frame has to land where a
/// cold one does.
fn plant(h: &mut Harness) -> Vec<WidgetId> {
    let plain = wtext("Wrapping").size(16).wrap(false).add(&mut h.rsc);
    let wrapped = wtext("Wrapping shapes").size(16).wrap(true).add(&mut h.rsc);
    let sized = SetSize {
        inner: wrapped.add_strong(&mut h.rsc),
        x: Some(Len::px(76.0)),
        y: None,
    }
    .add(&mut h.rsc);
    let aligned = Aligned {
        inner: sized.add_strong(&mut h.rsc),
        align: Align {
            x: Some(AxisAlign::Pos),
            y: Some(AxisAlign::Pos),
        },
    }
    .add(&mut h.rsc);
    let stack = Stack {
        children: vec![plain.add_strong(&mut h.rsc), aligned.add_strong(&mut h.rsc)],
        size: StackSize::Child(0),
    }
    .add(&mut h.rsc);
    let root = (stack,).span(Dir::RIGHT).add(&mut h.rsc);
    h.set_root(root);
    vec![
        plain.id(),
        wrapped.id(),
        sized.id(),
        aligned.id(),
        stack.id(),
        root.id(),
    ]
}

/// The first frame does not reach the layout a second one does, so "cold" is
/// not a fixed point and comparing against it compares against a tree that
/// has not settled.
#[test]
fn one_frame_is_enough() {
    let mut h = Harness::new((640, 900));
    let ids = plant(&mut h);
    let first = h.region(&ids[1]).unwrap();
    for _ in 0..3 {
        for &id in &ids {
            h.rsc.widgets_mut().get_dyn_mut(id);
        }
        h.frame();
    }
    let settled = h.region(&ids[1]).unwrap();
    println!(
        "first frame {} tall, settled {} tall",
        first.bot_right.y - first.top_left.y,
        settled.bot_right.y - settled.top_left.y
    );
    assert_eq!(
        first.bot_right.y - first.top_left.y,
        settled.bot_right.y - settled.top_left.y,
        "the first frame had not finished laying out"
    );
}

#[test]
fn repainting_everything_moves_nothing() {
    let mut warm = Harness::new((640, 900));
    let ids = plant(&mut warm);
    for &id in &ids {
        warm.rsc.widgets_mut().get_dyn_mut(id);
    }
    warm.frame();

    let mut cold = Harness::new((640, 900));
    let cold_ids = plant(&mut cold);

    let mut wrong = Vec::new();
    for (i, (&w, &c)) in ids.iter().zip(&cold_ids).enumerate() {
        let (got, want) = (warm.region(&w), cold.region(&c));
        if got != want {
            wrong.push(format!("widget {i}: warm {got:?} cold {want:?}"));
        }
    }
    assert!(wrong.is_empty(), "{}", wrong.join("\n"));
}

/// Six widgets, shrunk from 905. Everything inside the declared 189x176 box
/// is the same size whatever the output is, so a resize may not change any of
/// it -- but the text comes out 3.92px narrower warm than cold.
fn plant_fixed(h: &mut Harness) -> Vec<WidgetId> {
    let words = "Wrapping shapes one source into as many lines as the box leaves";
    let text = wtext(words).size(16).wrap(true).add(&mut h.rsc);
    let aligned = Aligned {
        inner: text.add_strong(&mut h.rsc),
        align: Align {
            x: Some(AxisAlign::Neg),
            y: None,
        },
    }
    .add(&mut h.rsc);
    let inner = (aligned,).span(Dir::RIGHT).add(&mut h.rsc);
    let sized = SetSize {
        inner: inner.add_strong(&mut h.rsc),
        x: Some(Len::px(189.0)),
        y: Some(Len::px(176.0)),
    }
    .add(&mut h.rsc);
    let filler = rect(Color::RED).add(&mut h.rsc);
    let root = (filler, sized).span(Dir::RIGHT).add(&mut h.rsc);
    h.state.root = Some(root.add_strong(&mut h.rsc));
    vec![
        text.id(),
        aligned.id(),
        inner.id(),
        sized.id(),
        filler.id(),
        root.id(),
    ]
}

#[test]
fn a_resize_does_not_reach_inside_a_box_of_declared_pixels() {
    let mut warm = Harness::new((1920, 1200));
    let ids = plant_fixed(&mut warm);
    warm.frame();
    warm.resize((640, 900));
    warm.frame();

    let mut cold = Harness::new((640, 900));
    let cold_ids = plant_fixed(&mut cold);
    cold.frame();

    let mut wrong = Vec::new();
    for (i, (&w, &c)) in ids.iter().zip(&cold_ids).enumerate() {
        let (got, want) = (warm.region(&w), cold.region(&c));
        if got != want {
            wrong.push(format!("widget {i}: warm {got:?} cold {want:?}"));
        }
    }
    assert!(wrong.is_empty(), "{}", wrong.join("\n"));
}

/// Four widgets, shrunk from 486. A span's two children are swapped: warm by
/// moving them, cold by growing them that way. Same widgets, same sizes, one
/// ends up 29.9px from where the other does.
fn plant_pair(h: &mut Harness, swapped: bool) -> (Vec<WidgetId>, WeakWidget<Span>) {
    let wrapped = wtext("Wrapping shapes one source into as many lines")
        .size(16)
        .wrap(true)
        .add(&mut h.rsc);
    let plain = wtext("one line, overflowing whatever it is given")
        .size(16)
        .wrap(false)
        .add(&mut h.rsc);
    let first: StrongWidget = wrapped.add_strong(&mut h.rsc);
    let second: StrongWidget = plain.add_strong(&mut h.rsc);
    let children = match swapped {
        true => vec![second, first],
        false => vec![first, second],
    };
    let span = Span {
        children,
        dir: Dir::RIGHT,
        gap: 0.0,
    }
    .add(&mut h.rsc);
    let span_handle = span;
    let aligned = Aligned {
        inner: span.add_strong(&mut h.rsc),
        align: Align {
            x: Some(AxisAlign::Center),
            y: None,
        },
    }
    .add(&mut h.rsc);
    h.state.root = Some(aligned.add_strong(&mut h.rsc));
    (
        vec![wrapped.id(), plain.id(), span.id(), aligned.id()],
        span_handle,
    )
}

#[test]
fn swapping_two_children_lands_where_growing_them_that_way_does() {
    let mut warm = Harness::new((640, 900));
    let (ids, span) = plant_pair(&mut warm, false);
    warm.frame();
    warm.rsc[span].children.rotate_left(1);
    warm.frame();

    let mut cold = Harness::new((640, 900));
    let (cold_ids, _) = plant_pair(&mut cold, true);
    cold.frame();

    let mut wrong = Vec::new();
    for (i, (&w, &c)) in ids.iter().zip(&cold_ids).enumerate() {
        let (got, want) = (warm.region(&w), cold.region(&c));
        if got != want {
            wrong.push(format!("widget {i}: warm {got:?} cold {want:?}"));
        }
    }
    assert!(wrong.is_empty(), "{}", wrong.join("\n"));
}