fix: more robust nixos check (#150)

Fixes #149.

.config/nextest.toml

@@ -0,0 +1,3 @@
+[profile.default]
+retries = { backoff = "exponential", count = 2, delay = "3s", jitter = true }
+slow-timeout = { period = "1m", terminate-after = 3 }

.github/workflows/ci.yml

@@ -27,8 +27,9 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           cache-on-failure: true
+      - uses: taiki-e/install-action@cargo-nextest
       - name: test
-        run: cargo test --workspace --all-targets
+        run: cargo nextest run --workspace --all-targets
 
   feature-checks:
     runs-on: ubuntu-latest

crates/svm-rs/src/install.rs

@@ -212,7 +212,7 @@ fn patch_for_nixos(bin: &Path) -> Result<(), SvmError> {
             bin.display()
         ))
         .output()
-        .expect("Failed to execute command");
+        .map_err(|e| SvmError::CouldNotPatchForNixOs(String::new(), e.to_string()))?;
 
     match output.status.success() {
         true => Ok(()),

crates/svm-rs/src/paths.rs

@@ -53,6 +53,7 @@ pub fn data_dir() -> &'static Path {
     })
 }
 
+#[allow(dead_code)]
 fn resolve_data_dir() -> PathBuf {
     let home_dir = dirs::home_dir()
         .expect("could not detect user home directory")
@@ -102,20 +103,3 @@ pub fn version_binary(version: &str) -> PathBuf {
     binary.push(version);
     PathBuf::from(binary)
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_data_dir_resolution() {
-        let home_dir = dirs::home_dir().unwrap().join(".svm");
-        let data_dir = dirs::data_dir();
-        let resolved_dir = resolve_data_dir();
-        if home_dir.exists() || data_dir.is_none() {
-            assert_eq!(resolved_dir, home_dir);
-        } else {
-            assert_eq!(resolved_dir, data_dir.unwrap().join("svm"));
-        }
-    }
-}

crates/svm-rs/src/platform.rs

@@ -43,7 +43,10 @@ impl FromStr for Platform {
 }
 
 pub fn is_nixos() -> bool {
-    std::path::Path::new("/etc/NIXOS").exists()
+    cfg!(target_os = "linux")
+        && (std::path::Path::new("/etc/nixos").exists()
+            || std::path::Path::new("/etc/NIXOS").exists())
+        && std::fs::read_to_string("/etc/os-release").is_ok_and(|s| s.contains("NixOS"))
 }
 
 /// Read the current machine's platform.