build: mark untestable function to be excluded from mutation tests

Cargo.toml

@@ -22,5 +22,7 @@ assert2 = "0.3"
 pretty_assertions = "1.4"
 rstest = "0.23"
 
+mutants = "0.0"
+
 [lints.rust]
 unexpected_cfgs = { level = "warn", check-cfg = ['cfg(tarpaulin_include)'] }

src/main.rs

@@ -17,6 +17,7 @@ mod tests;
 
 #[tokio::main]
 #[cfg(not(tarpaulin_include))]
+#[cfg_attr(test, mutants::skip)]
 async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
     let github_workspace = std::env::var("GITHUB_WORKSPACE").context("GITHUB_WORKSPACE")?;
     let fs = kxio::fs::new(github_workspace);

src/printer.rs

@@ -6,6 +6,7 @@ pub trait Printer {
 pub struct StandardPrinter;
 impl Printer for StandardPrinter {
     #[cfg(not(tarpaulin_include))]
+    #[cfg_attr(test, mutants::skip)]
     fn println(&self, message: impl Into<String>) {
         println!("{}", message.into());
     }