iris/tests/generated.rs

//! Laying a tree out again has to land where growing it that way would.
//!
//! Every case is one of `scenario`'s, over the trees `iris::random` grows
//! from a seed. The fast test takes a handful of seeds and the ignored one
//! takes as many as it is asked for; both run the same cases the shrinker
//! does over the same trees, so a seed that fails here is reduced by
//!
//!     SHRINK_SEED=<seed> SHRINK_DEPTH=<depth> SHRINK_CASE=<case> \
//!       cargo test --release --test shrink -- --ignored --nocapture
//!
//! `IRIS_GENERATED_SEED`, `IRIS_GENERATED_SEEDS` and `IRIS_GENERATED_DEPTH`
//! select what the long run covers.

mod rig;
#[path = "scenario/mod.rs"]
mod scenario;

use iris::random::{Edits, Plan, plan};
use rig::env;
use scenario::{ALL, Case, diverges, over_seeds};

/// How deep the generator branches. The generator widens two to four ways per
/// level, so depth is exponential in width and a deep narrow tree is not
/// reachable by raising this -- it buys more overlap between dependency
/// paths, not more ancestry.
fn depth() -> usize {
    env("IRIS_GENERATED_DEPTH", 4)
}

/// The seeds the ordinary tests take: a corpus rather than a set of
/// regression cases, since a seed names a tree only for as long as the
/// generator draws the same things in the same order. Adding images to the
/// leaves moved every one of them, so 20 and 86 -- which once caught a widget
/// placed twice in a box its parent had already placed it in, and a `Scroll`
/// fixed point settling differently -- no longer grow those trees. Both
/// defects are pinned by the shrunk fixtures in `cases/unsettled.rs`, which
/// are trees rather than numbers.
const SEEDS: [u64; 10] = [1, 2, 3, 5, 8, 10, 13, 20, 86, 98];

fn check(seed: u64, depth: usize, case: Case) {
    check_plan(&plan(seed, depth, &Edits::default()), seed, depth, case);
}

fn check_plan(grown: &Plan, seed: u64, depth: usize, case: Case) {
    if let Some(how) = diverges(grown, case, seed) {
        panic!(
            "seed {seed} at depth {depth} differs after {}: {how}\n\
             reduce it with SHRINK_SEED={seed} SHRINK_DEPTH={depth} \
             SHRINK_CASE={} cargo test --release --test shrink -- --ignored --nocapture",
            case.name(),
            case.name(),
        );
    }
}

/// A test per case, and the list of which cases have one, from the same
/// place. A case the ordinary suite leaves out runs only in the long scan,
/// which nobody runs by hand.
macro_rules! cases {
    ($($name:ident = $case:expr,)*) => {
        $(
            #[test]
            fn $name() {
                for seed in SEEDS {
                    check(seed, depth(), $case);
                }
            }
        )*

        const NAMED: [Case; [$($case,)*].len()] = [$($case,)*];
    };
}

cases! {
    many_widgets_redrawing_at_once_leaves_every_box_where_it_was = Case::RepaintSome,
    everything_redrawing_at_once_leaves_every_box_where_it_was = Case::Repaint,
    a_resize_lands_where_starting_at_that_size_would = Case::Resize,
    a_resize_and_a_repaint_land_where_starting_that_way_would = Case::ResizeRepaint,
    a_size_change_after_a_resize_lands_the_same_way = Case::ResizeSize,
    a_resize_after_a_size_change_lands_the_same_way = Case::SizeResize,
    a_size_change_lands_where_growing_it_that_way_would = Case::Size,
    every_size_changing_at_once_lands_where_growing_it_that_way_would = Case::EverySize,
    an_alignment_change_lands_where_growing_it_that_way_would = Case::Align,
    giving_and_taking_a_movable_region_rebuilds_what_resolves_it = Case::RegionNode,
    reordering_a_span_lands_where_growing_it_that_way_would = Case::Reorder,
}

/// The shuffles are one test between them, so they are the only cases `ALL`
/// may hold without a test of their own.
#[test]
fn every_case_runs_without_the_long_scan() {
    for case in ALL {
        assert!(
            NAMED.contains(&case) || matches!(case, Case::Shuffle(_)),
            "{} runs only in the long seed scan; give it a case here",
            case.name()
        );
    }
}

#[test]
fn adding_and_removing_span_children_lands_where_growing_it_that_way_would() {
    for case in ALL {
        if matches!(case, Case::Shuffle(_)) {
            for seed in SEEDS {
                check(seed, depth(), case);
            }
        }
    }
}

#[test]
#[ignore = "as many seeds as it is asked for, rather than the ten the others check"]
fn a_long_run_of_seeds_agrees() {
    let depth = depth();
    let seeds: Vec<u64> = match std::env::var("IRIS_GENERATED_SEED")
        .ok()
        .and_then(|v| v.parse().ok())
    {
        Some(seed) => vec![seed],
        None => (1..=env("IRIS_GENERATED_SEEDS", 100_u64)).collect(),
    };
    over_seeds(seeds, |seed| {
        let grown = plan(seed, depth, &Edits::default());
        for case in ALL {
            check_plan(&grown, seed, depth, case);
        }
    });
}