[−][src]Module fluid::wiki::assertions_list

The complete list of the implemented assertions.

Note that the assertions marked as consuming consume the left part of the assertion, so there cannot be a chain of multiple assertions.

Those assertions print a more complete error message in the test functions marked as #[fact] or #[attribute]. They can be used in a standard #[test] function as well, but in this case, the location and the stringified version of the left side are not displayed in the failure message.

Various features

Negation

(2 + 2).should().not().be_equal_to(5);

Chaining

"42".parse::<i32>().should().not().be_an_error()
    .and_should().yield_the_item(42);

Explanation

fn the_answer() -> i32 {
    42
}

the_answer().should().be_equal_to(42).because("42 is the answer to the question");

Equality

(1 + 1).should().be_equal_to(2);

With precision (for floats only):

#[cfg(feature = "float")]
(0.999 * 2.).should().be_equal_to(2.01).with_precision(0.1);

`Iterator`s (consuming assertions)

Checking if contain something

Some(2).should().yield_the_item(2);

vec![1, 2, 3].into_iter().should().yield_the_item(1);

Collections

Checking if empty

let empty_list = std::collections::LinkedList::<i32>::new();

empty_list.should().be_empty();

Checking if contain something

let empty_list = std::collections::LinkedList::<i32>::new();

vec![1, 2, 3].should().contain(1);

`Result`s

Checking if it is ok

"123".parse::<i32>().should().be_ok();

Note that you can also use the iterator assertions.

Checking if it is an error

"?".parse::<i32>().should().be_an_error();

Strings

Checking if it is empty

"".should().be_empty();

Checking if it contains something

let sentence = "Hello world.";

sentence.should().contain("Hello");
sentence.should().contain('.');
sentence.should().contain(['.', ' ']);
sentence.should().not().contain(char::is_numeric);

Checking if it starts with something

let sentence = "Hello world.";

sentence.should().start_with(char::is_alphabetic);
sentence.should().start_with("Hello");

Checking if it ends with something

let sentence = "Hello world.";

sentence.should().not().end_with(char::is_alphabetic);
sentence.should().end_with('.');

Boolean


Some(0).is_some().should().be_true();
(2 + 2 == 5).should().be_false();

Generic

When there is no specific needed assertion:

fn foo() -> i32 {
    42
}

foo().should().have_the_property(|&n| n % 2 == 0)
    .because("the number must be even");