Adding `expecting` library as a dependency

Run this command in a terminal, in your project's directory:

cargo add expecting

To add it manually, edit your project's Cargo.toml file and add to the [dependencies] section:

expecting = "0.6.0"

The expecting library will be automatically available globally. Read the expecting library documentation.

Back to the crate overview.

Readme

Expecting

Expecting provides macros for testing conditions without panicking. The expect_* family of macros cause an early return of anyhow::Error if the expected condition is not met.

Macro	Description
`expect!(condition)`	Expects `condition` to be `true`
`expect_eq!(a, b)`	Expects `a == b`
`expect_ne!(a, b)`	Expects `a != b`
`expect_some(option)`	Expects `option` to be `Some(x)` and returns `x`
`expect_some_eq(some_a, a)`	Expects `some_a == Some(a)`
`expect_none(option)`	Expects `option` to be `None`
`expect_ok(result)`	Expects `result` to be `Ok(x)` and returns `x`
`expect_err(result)`	Expects `result` to be `Err(e)` and returns `e`
`expect_contains(string, substr)`	Expects `string` to contain `substr`
`expect_contains(container, element)`	Expects `container` (e.g., `Vec`) to contain `element`
`expect_empty(container)`	Expects `container` to have no elements.
`expect_empty(string)`	Expects `string` to have a length of zero.
`expect_not_empty(container)`	Expects `container` to have 1+ elements.
`expect_not_empty(string)`	Expects `string` to have non-zero length.

This crate is especially helpful in async integration tests that involve provisioning and tearing down resources; rather than struggle to catch panics, you can simply use expect_* instead of assert_* to return Result.

Examples

use expecting::expect_eq;

#[test]
fn passing_test() -> Result<()> {
    expect_eq!(1, 1);
    Ok(())
}

#[test]
fn failing_test() -> Result<()> {
    expect_eq!(1, 2);  // returns early
    Ok(())  // won't be reached
}

The error message for a failed test includes the line number and detailed description of what went wrong.

expect_eq error

expect_contains error

See the docs for usage examples and more info.

Adding expecting library as a dependency

Adding `expecting` library as a dependency