How do I disable an entire example based on features?

Question

My Rust project has examples that are only relevant to certain features.

I can ignore the main function with:

#[cfg(feature = "foo")]
fn main() {

But other statements that depend on the feature cause errors when I run cargo test. So I have to use a number of cfg attribute statements on functions and use statements to disable code that depends on the feature.

Is there a way to just ignore an entire example file based on the feature configuration?

Also, because main is hidden without the feature, cargo test has this error:

error: main function not found

So this isn't a good solution.

Answer 1

Make more specific use of the #[cfg] directive, providing both a main() when foo is enabled, and a main() when foo is not:

extern crate blah;
// other code which will still compile even without "foo" feature

#[cfg(feature = "foo")]
fn main() {
    use blah::OnlyExistsWithFoo;
    // code which requires "foo" feature
}

#[cfg(not(feature = "foo"))]
fn main() {
    // empty main function for when "foo" is disabled
}