Add a test for bare linker configuration

cargo-auditable/tests/fixtures/bare_linker/.cargo/config.toml

@@ -0,0 +1,33 @@
+# copied from https://github.com/EFForg/rayhunter/blob/adeeb751667d3b44ba6ad215a1bc0ac73d90ae72/.cargo/config.toml#L1
+# as a motivating example for bare linker support
+
+[target.aarch64-apple-darwin]
+linker = "rust-lld"
+rustflags = ["-C", "target-feature=+crt-static"]
+
+[target.aarch64-unknown-linux-musl]
+linker = "rust-lld"
+rustflags = ["-C", "target-feature=+crt-static"]
+
+# apt install build-essential libc6-armhf-cross libc6-dev-armhf-cross gcc-arm-linux-gnueabihf
+[target.armv7-unknown-linux-gnueabihf]
+linker = "arm-linux-gnueabihf-gcc"
+rustflags = ["-C", "target-feature=+crt-static"]
+
+[target.armv7-unknown-linux-musleabihf]
+linker = "rust-lld"
+rustflags = ["-C", "target-feature=+crt-static"]
+
+[target.armv7-unknown-linux-musleabi]
+linker = "rust-lld"
+rustflags = ["-C", "target-feature=+crt-static"]
+
+# Disable rust-lld for x86 macOS because the linker crashers when compiling
+# the installer in release mode with debug info on.
+# [target.x86_64-apple-darwin]
+# linker = "rust-lld"
+# rustflags = ["-C", "target-feature=+crt-static"]
+
+[target.x86_64-unknown-linux-musl]
+linker = "rust-lld"
+rustflags = ["-C", "target-feature=+crt-static"]

cargo-auditable/tests/fixtures/bare_linker/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "bare_linker"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+
+[workspace]

cargo-auditable/tests/fixtures/bare_linker/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

cargo-auditable/tests/it.rs

@@ -585,3 +585,35 @@ fn test_proc_macro_inner(sbom: bool) {
         .expect("Could not find 'syn' in the embedded dependency list!");
     assert_eq!(syn_info.kind, DependencyKind::Build);
 }
+
+#[test]
+fn test_bare_linker() {
+    test_bare_linker_inner(false);
+    test_bare_linker_inner(true);
+}
+fn test_bare_linker_inner(sbom: bool) {
+    // Path to workspace fixture Cargo.toml
+    let cargo_toml =
+        PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("tests/fixtures/bare_linker/Cargo.toml");
+    // The motivating example is https://github.com/EFForg/rayhunter/blob/main/.cargo/config.toml
+    // and the config file fixture is based on that.
+    // There doesn't seem to be a way to build with a bare linker for GNU targets, only Apple and Musl,
+    // so this tests really only does anything on those.
+    let config_path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .join("tests/fixtures/bare_linker/.cargo/config.toml");
+
+    let bins = run_cargo_auditable(
+        cargo_toml,
+        &["--config", config_path.to_str().unwrap()],
+        &[],
+        sbom,
+    );
+    eprintln!("Test fixture binary map: {bins:?}");
+
+    // bare_linker should only depend on itself
+    let bare_linker_bin = &bins.get("bare_linker").unwrap()[0];
+    let dep_info = get_dependency_info(bare_linker_bin);
+    eprintln!("{bare_linker_bin} dependency info: {dep_info:?}");
+    assert!(dep_info.packages.len() == 1);
+    assert!(dep_info.packages.iter().any(|p| p.name == "bare_linker"));
+}