Struct arithmetic_eval::fns::AssertFails

pub struct AssertFails { /* private fields */ }

Assertion that the provided function raises an error. Errors can optionally be matched against a predicate.

If an error is raised, but does not match the predicate, it is bubbled up.

Type

(using arithmetic-typing notation)

(() -> 'T) -> ()

Examples

let program = "
    obj = #{ x: 3 };
    assert_fails(|| obj.x + obj.y); // pass: `obj.y` is not defined
    assert_fails(|| obj.x); // fail: function executes successfully
";
let module = Untyped::<F32Grammar>::parse_statements(program)?;
let module = ExecutableModule::new("test_assert", &module)?;

let mut env = Environment::new();
env.insert_native_fn("assert_fails", fns::AssertFails::default());

let err = module.with_env(&env)?.run().unwrap_err();
assert_eq!(
    err.source().location().in_module().span(program),
    "assert_fails(|| obj.x)"
);

Custom error matching:

let assert_fails = fns::AssertFails::new(|err| {
    matches!(err.kind(), ErrorKind::NativeCall(_))
});

let program = "
    assert_fails(|| assert_fails(1)); // pass: native error
    assert_fails(assert_fails); // fail: arg len mismatch
";
let module = Untyped::<F32Grammar>::parse_statements(program)?;
let module = ExecutableModule::new("test_assert", &module)?;

let mut env = Environment::new();
env.insert_native_fn("assert_fails", assert_fails);

let err = module.with_env(&env)?.run().unwrap_err();
assert_eq!(
    err.source().location().in_module().span(program),
    "assert_fails(assert_fails)"
);

Implementations

impl AssertFails

pub fn new(error_matcher: fn(_: &Error) -> bool) -> Self

Creates an assertion function with a custom error matcher. If the error does not match, the assertion will fail, and the error will bubble up.

Trait Implementations

impl Clone for AssertFails

fn clone(&self) -> AssertFails

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AssertFails

fn fmt(&self, formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for AssertFails

fn default() -> Self

Returns the “default value” for a type.

impl<T: 'static + Clone> NativeFn<T> for AssertFails

fn evaluate( &self, args: Vec<SpannedValue<T>>, ctx: &mut CallContext<'_, T> ) -> EvalResult<T>

Executes the function on the specified arguments.

impl Copy for AssertFails