litmus

a macro-free BDD test harness.
inspired by cucumber and rspec.

Why litmus

With litmus, you can ...

write tests declaratively
  with minimal overhead
   all without using macros.

Major design criteria

• works with cargo-test and cargo-nextest
• offers Gherkin-ish ergonomics
• is fast

Quickstart

Add this to your Cargo.toml:

# ./Cargo.toml

[dev-dependencies]
litmus = "0.5.5"

Disable the default harness for your test targets:

# ./Cargo.toml

[[test]]
name = ...
path = ...
harness = false

Examples

The following example replicates the cucumber-rs example.

/// ./examples/hello-world.rs

#[derive(::core::default::Default)]
struct World {
    user: ::core::option::Option<String>,
    capacity: usize,
}

#[rustfmt::skip]
fn main() -> ::std::process::ExitCode {
    ::litmus::Runner::new()
        .feature(::litmus::Feature::new()
            .description("Eating too much cucumbers may not be good for you")
            .scenario(::litmus::Scenario::<World>::new()
                .description("Eating a few isn't a problem")
                .given("Alice is hungry", |w| w.user = Some("Alice".to_owned()))
                .when("she eats 3 cucumbers", |w| {
                    w.capacity += 3;
                    ::litmus::assert!(w.capacity < 4, "Alice exploded")
                })
                .then("she is full", |w| ::litmus::assert!(w.capacity == 3, "Alice isn't full!"))))
        .run()
}

# ./Cargo.toml

[[example]]
name = "hello-world"
path = "./examples/hello-world.rs"
harness = false

We recommend cargo-nextest for a better experience, although cargo-test is supported.

$ cargo nextest run --example hello-world
    Finished `test` profile [unoptimized + debuginfo] target(s) in 0.14s
────────────
 Nextest run ID 72000e08-3cd4-4b80-a32d-a50a382f1673 with nextest profile: default
    Starting 1 test across 1 binary
        PASS [   0.007s] litmus::example/hello-world Eating a few isn't a problem
────────────
     Summary [   0.008s] 1 test run: 1 passed, 0 skipped

$ cargo test --example hello-world
    Finished `test` profile [unoptimized + debuginfo] target(s) in 0.17s
     Running unittests examples/hello-world.rs (target/debug/examples/hello_world-06cfa831d0c9efe7)

running 1 test
test Eating a few isn't a problem ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

More examples are available in the examples/ directory.

License

This project is licensed under the BSD 3-Clause License.