1 files changed, 109 insertions, 0 deletions
diff --git a/vendor/rustix/tests/backends.rs b/vendor/rustix/tests/backends.rs
new file mode 100644
index 000000000..4b88bd11c
--- /dev/null
+++ b/vendor/rustix/tests/backends.rs
@@ -0,0 +1,109 @@
+use std::process::Command;
+
+#[test]
+fn test_backends() {
+    // Pick an arbitrary platform where linux_raw is enabled by default and
+    // ensure that the use-default crate uses it.
+    #[cfg(all(target_os = "linux", target_arch = "aarch64"))]
+    {
+        assert!(
+            !has_dependency("test-crates/use-default", &[], &[], &["RUSTFLAGS"], "libc"),
+            "use-default depends on libc"
+        );
+        assert!(
+            has_dependency(
+                "test-crates/use-default",
+                &[],
+                &[],
+                &["RUSTFLAGS"],
+                "linux-raw-sys"
+            ),
+            "use-default does not depend on linux-raw-sys"
+        );
+    }
+
+    #[cfg(windows)]
+    let libc_dep = "windows-sys";
+    #[cfg(unix)]
+    let libc_dep = "libc";
+
+    // Test the use-libc crate, which enables the "use-libc" cargo feature.
+    assert!(
+        has_dependency("test-crates/use-libc", &[], &[], &["RUSTFLAGS"], libc_dep),
+        "use-libc doesn't depend on {}",
+        libc_dep
+    );
+
+    // Test the use-default crate with `--cfg=rustix_use_libc`.
+    assert!(
+        has_dependency(
+            "test-crates/use-default",
+            &[],
+            &[("RUSTFLAGS", "--cfg=rustix_use_libc")],
+            &[],
+            libc_dep
+        ),
+        "use-default with --cfg=rustix_use_libc does not depend on {}",
+        libc_dep
+    );
+    assert!(
+        !has_dependency(
+            "test-crates/use-default",
+            &[],
+            &[("RUSTFLAGS", "--cfg=rustix_use_libc")],
+            &[],
+            "linux-raw-sys"
+        ),
+        "use-default with --cfg=rustix_use_libc depends on linux-raw-sys"
+    );
+
+    // Test the use-default crate with `--features=rustix/use-libc`.
+    assert!(
+        has_dependency(
+            "test-crates/use-default",
+            &["--features=rustix/use-libc"],
+            &[],
+            &[],
+            libc_dep
+        ),
+        "use-default with --features=rustix/use-libc does not depend on {}",
+        libc_dep
+    );
+}
+
+/// Test whether the crate at directory `dir` has a dependency on `dependency`,
+/// setting the environment variables `envs` and unsetting the environment
+/// variables `remove_envs` when running `cargo`.
+fn has_dependency(
+    dir: &str,
+    args: &[&str],
+    envs: &[(&str, &str)],
+    remove_envs: &[&str],
+    dependency: &str,
+) -> bool {
+    let mut command = Command::new("cargo");
+
+    command
+        .arg("tree")
+        .arg("--quiet")
+        .arg("--edges=normal")
+        .arg(&format!("--invert={}", dependency))
+        .current_dir(dir);
+
+    command.args(args);
+    for (key, value) in envs {
+        command.env(key, value);
+    }
+    for key in remove_envs {
+        command.env_remove(key);
+    }
+
+    let child = command.output().unwrap();
+
+    // `cargo tree --invert=foo` can fail in two different ways: it exits with
+    // a non-zero status if the dependency is not present in the Cargo.toml
+    // configuration, and it exists with a zero status and prints nothing if
+    // the dependency is present but optional and not enabled. So we check for
+    // both here.
+    child.status.success() && !child.stdout.is_empty()
+}