Crate diceprop[−][src]

Expand description

A collection of mathematical properties for random testing.

It’s based on dicetest.

Status of this crate

The author does not consider this crate as stable yet. Changes will be documented in the changelog.

Examples

Associative binary operation

``````use diceprop::{props, Fun2, Set};
use dicetest::prelude::*;

#[test]
Dicetest::repeatedly().run(|mut fate| {
let set = Set::new("f32 ∩ [-100,100]", dice::f32(-100.0..=100.0));
let vars = fate.roll(set.vars(["x", "y", "z"]));
let add = Fun2::infix("+", |x, y| x + y);
})
}``````

The test fails with the following output:

``````The test failed after 12 passes.

- seed: 14859458141222391139
- start limit: 0
- end limit: 100
- passes: 200

- run code: "2pYRCj9fj8sV52fB5iyFhxCISGY3nKlMzlzIKq0NKLwGAAAAAAAAAA=="
- limit: 6
- hints:
- Is `+` associative?
- x, y, z of f32 ∩ [-100,100]
- x = 96.621735
- y = -90.97134
- z = -8.10239
- (x + y) = 5.6503983
- ((x + y) + z) = -2.451992
- (y + z) = -99.07373
- (x + (y + z)) = -2.4519958
- (((x + y) + z) == (x + (y + z))) = false
- error: assertion failed: (((x + y) + z) == (x + (y + z)))``````

Left inverse function

``````use diceprop::{props, Fun1, Set};
use dicetest::prelude::*;

#[test]
fn sqrt_is_left_inverse_of_sq_for_non_negative_f32() {
Dicetest::repeatedly().run(|mut fate| {
let set = Set::new("f32 ∩ [0,+∞]", dice::f32(0.0..));
let vars = fate.roll(set.vars(["x"]));
let sq = Fun1::postfix("²", |x| x * x);
let sqrt = Fun1::new("√", |x: f32| x.sqrt());
props::fun::left_inverse(vars, sq, sqrt);
})
}``````

The test fails with the following output:

``````The test failed after 0 passes.

- seed: 7632522237817347676
- start limit: 0
- end limit: 100
- passes: 200

- run code: "F2/nnlbX6qyCOm5MU7P8BSXdnJ4XNXJdihgwhtWxlzMAAAAAAAAAAA=="
- limit: 0
- hints:
- Is `√` left inverse of `²`?
- x of f32 ∩ [0,+∞]
- x = 305770290000000000000000000000000000000.0
- (x)² = inf
- √((x)²) = inf
- (√((x)²) == x) = false
- error: assertion failed: (√((x)²) == x)``````

Partial order

``````use diceprop::{props, Fun2, Set};
use dicetest::prelude::*;

#[test]
fn gt_is_partial_order_for_any_f32() {
Dicetest::repeatedly().run(|mut fate| {
let set = Set::new("f32", dice::any_f32());
let vars = fate.roll(set.vars(["x", "y", "z"]));
let gt = Fun2::infix("≤", |x, y| x <= y);
props::binrel::partial_order(vars, gt);
})
}``````

The test fails with the following output:

``````The test failed after 3 passes.

- seed: 18374838706510982620
- start limit: 0
- end limit: 100
- passes: 200

- run code: "h6jQMNr6fi/j9OZOXmklXYAUATM96EpE6+DENMhSZHkBAAAAAAAAAA=="
- limit: 1
- hints:
- Is `≤` a partial order?
- Is `≤` reflexive?
- x of f32
- x = NaN
- (x ≤ x) = false
- error: assertion failed: (x ≤ x)``````

Modules

A collection of operations on `Eval` that are useful for writing properties.

A collection of properties that can be verified with randomly generated test data.

Structs

Represents an element of type `S`.

Represents a evaluated expression of type `S`.

Represents a function of arity 1.

A human-readable label that describes a `Fun1` applied to an argument.

Represents a function of arity 2.

A human-readable label that describes a `Fun2` applied to arguments.

Represents a function of arity 3.

A human-readable label that describes a `Fun3` applied to arguments.

A mathematical set that can be used to randomly choose `Vars`.

Represents elements that were chosen from a set and that can be used as variables in properties.