Add basic test

tests/common.rs

@@ -0,0 +1,47 @@
+// SPDX-FileCopyrightText: 2022 Matteo Settenvini <matteo.settenvini@montecristosoftware.eu>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+use {
+    anyhow::{ensure, Result},
+    std::ffi::CString,
+    std::os::raw::c_int,
+    std::os::unix::fs::symlink,
+    std::path::PathBuf,
+    std::sync::Once,
+};
+
+include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
+
+static SETUP: Once = Once::new();
+
+pub fn setup() -> Result<()> {
+    unsafe {
+        static mut NSS_CONFIG_STATUS: c_int = 0;
+        SETUP.call_once(|| {
+            let out_dir = PathBuf::from(env!("OUT_DIR"));
+            let library_path = test_cdylib::build_current_project();
+            let mut library_filename = library_path.file_name().unwrap().to_owned();
+            library_filename.push(".2"); // required for NSS 2 modules
+
+            let dest = out_dir.join(library_filename);
+            symlink(&library_path, &dest).expect(&format!(
+                "Unable to create symlink to library ({} -> {})",
+                library_path.to_string_lossy(),
+                dest.to_string_lossy()
+            ));
+
+            std::env::set_var("LD_LIBRARY_PATH", out_dir);
+
+            let db = CString::new("hosts").unwrap();
+            let resolvers = CString::new("files malcontent [UNAVAIL=return] dns").unwrap();
+            NSS_CONFIG_STATUS = __nss_configure_lookup(db.as_ptr(), resolvers.as_ptr());
+        });
+
+        ensure!(
+            NSS_CONFIG_STATUS == 0,
+            "Unable to configure NSS to load module: __nss_configure_lookup() returned {}",
+            NSS_CONFIG_STATUS
+        );
+        Ok(())
+    }
+}

tests/integration_test.rs

@@ -0,0 +1,15 @@
+// SPDX-FileCopyrightText: 2022 Matteo Settenvini <matteo.settenvini@montecristosoftware.eu>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+mod common;
+
+use anyhow::Result;
+
+#[test]
+fn nss_module_is_loaded() -> Result<()> {
+    use std::net::ToSocketAddrs;
+
+    common::setup()?;
+    "www.google.com:443".to_socket_addrs()?;
+    Ok(())
+}