2 files changed, 268 insertions, 0 deletions
diff --git a/tvix/store/src/tests/mod.rs b/tvix/store/src/tests/mod.rs
index 4022c329798b..57ae1df9f6ff 100644
--- a/tvix/store/src/tests/mod.rs
+++ b/tvix/store/src/tests/mod.rs
@@ -1,5 +1,6 @@
 mod directory;
 mod directory_nodes_iterator;
 mod directory_service;
+mod nar;
 mod path_info_service;
 mod pathinfo;
diff --git a/tvix/store/src/tests/nar.rs b/tvix/store/src/tests/nar.rs
new file mode 100644
index 000000000000..5a865f52b492
--- /dev/null
+++ b/tvix/store/src/tests/nar.rs
@@ -0,0 +1,267 @@
+use data_encoding::BASE64;
+
+use crate::client::StoreClient;
+use crate::nar::write_nar;
+use crate::proto;
+use crate::proto::DirectoryNode;
+use crate::proto::FileNode;
+use crate::proto::SymlinkNode;
+use lazy_static::lazy_static;
+
+const HELLOWORLD_BLOB_CONTENTS: &[u8] = b"Hello World!";
+const EMPTY_BLOB_CONTENTS: &[u8] = b"";
+
+lazy_static! {
+    static ref HELLOWORLD_BLOB_DIGEST: Vec<u8> =
+        blake3::hash(HELLOWORLD_BLOB_CONTENTS).as_bytes().to_vec();
+    static ref EMPTY_BLOB_DIGEST: Vec<u8> = blake3::hash(EMPTY_BLOB_CONTENTS).as_bytes().to_vec();
+    static ref DIRECTORY_WITH_KEEP: proto::Directory = proto::Directory {
+        directories: vec![],
+        files: vec![FileNode {
+            name: ".keep".to_string(),
+            digest: EMPTY_BLOB_DIGEST.to_vec(),
+            size: 0,
+            executable: false,
+        }],
+        symlinks: vec![],
+    };
+    static ref DIRECTORY_COMPLICATED: proto::Directory = proto::Directory {
+        directories: vec![DirectoryNode {
+            name: "keep".to_string(),
+            digest: DIRECTORY_WITH_KEEP.digest(),
+            size: DIRECTORY_WITH_KEEP.size(),
+        }],
+        files: vec![FileNode {
+            name: ".keep".to_string(),
+            digest: EMPTY_BLOB_DIGEST.to_vec(),
+            size: 0,
+            executable: false,
+        }],
+        symlinks: vec![SymlinkNode {
+            name: "aa".to_string(),
+            target: "/nix/store/somewhereelse".to_string(),
+        }],
+    };
+}
+
+/// A Store client that fails if you ask it for a blob or a directory
+#[derive(Default)]
+struct FailingStoreClient {}
+
+impl StoreClient for FailingStoreClient {
+    fn open_blob(&self, digest: Vec<u8>) -> std::io::Result<Box<dyn std::io::BufRead>> {
+        panic!(
+            "open_blob should never be called, but was called with {}",
+            BASE64.encode(&digest),
+        );
+    }
+
+    fn get_directory(&self, digest: Vec<u8>) -> std::io::Result<Option<proto::Directory>> {
+        panic!(
+            "get_directory should never be called, but was called with {}",
+            BASE64.encode(&digest),
+        );
+    }
+}
+
+/// Only allow a request for a blob with [HELLOWORLD_BLOB_DIGEST]
+/// panic on everything else.
+#[derive(Default)]
+struct HelloWorldBlobStoreClient {}
+
+impl StoreClient for HelloWorldBlobStoreClient {
+    fn open_blob(&self, digest: Vec<u8>) -> std::io::Result<Box<dyn std::io::BufRead>> {
+        if digest != HELLOWORLD_BLOB_DIGEST.to_vec() {
+            panic!("open_blob called with {}", BASE64.encode(&digest));
+        }
+
+        let b: Box<&[u8]> = Box::new(&HELLOWORLD_BLOB_CONTENTS);
+
+        Ok(b)
+    }
+
+    fn get_directory(&self, digest: Vec<u8>) -> std::io::Result<Option<proto::Directory>> {
+        panic!(
+            "get_directory should never be called, but was called with {}",
+            BASE64.encode(&digest),
+        );
+    }
+}
+
+/// Allow blob requests for [HELLOWORLD_BLOB_DIGEST] and EMPTY_BLOB_DIGEST, and
+/// allow DIRECTORY_WITH_KEEP and DIRECTORY_COMPLICATED.
+#[derive(Default)]
+struct SomeDirectoryStoreClient {}
+
+impl StoreClient for SomeDirectoryStoreClient {
+    fn open_blob(&self, digest: Vec<u8>) -> std::io::Result<Box<dyn std::io::BufRead>> {
+        if digest == HELLOWORLD_BLOB_DIGEST.to_vec() {
+            let b: Box<&[u8]> = Box::new(&HELLOWORLD_BLOB_CONTENTS);
+            return Ok(b);
+        }
+        if digest == EMPTY_BLOB_DIGEST.to_vec() {
+            let b: Box<&[u8]> = Box::new(&EMPTY_BLOB_CONTENTS);
+            return Ok(b);
+        }
+        panic!("open_blob called with {}", BASE64.encode(&digest));
+    }
+
+    fn get_directory(&self, digest: Vec<u8>) -> std::io::Result<Option<proto::Directory>> {
+        if digest == DIRECTORY_WITH_KEEP.digest() {
+            return Ok(Some(DIRECTORY_WITH_KEEP.clone()));
+        }
+        if digest == DIRECTORY_COMPLICATED.digest() {
+            return Ok(Some(DIRECTORY_COMPLICATED.clone()));
+        }
+        panic!("get_directory called with {}", BASE64.encode(&digest));
+    }
+}
+
+#[tokio::test]
+async fn single_symlink() -> anyhow::Result<()> {
+    let mut buf: Vec<u8> = vec![];
+    let mut store_client = FailingStoreClient::default();
+
+    write_nar(
+        &mut buf,
+        crate::proto::node::Node::Symlink(SymlinkNode {
+            name: "doesntmatter".to_string(),
+            target: "/nix/store/somewhereelse".to_string(),
+        }),
+        &mut store_client,
+    )
+    .expect("must succeed");
+
+    assert_eq!(
+        buf,
+        vec![
+            13, 0, 0, 0, 0, 0, 0, 0, 110, 105, 120, 45, 97, 114, 99, 104, 105, 118, 101, 45, 49, 0,
+            0, 0, // "nix-archive-1"
+            1, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, // "("
+            4, 0, 0, 0, 0, 0, 0, 0, 116, 121, 112, 101, 0, 0, 0, 0, // "type"
+            7, 0, 0, 0, 0, 0, 0, 0, 115, 121, 109, 108, 105, 110, 107, 0, // "symlink"
+            6, 0, 0, 0, 0, 0, 0, 0, 116, 97, 114, 103, 101, 116, 0, 0, // target
+            24, 0, 0, 0, 0, 0, 0, 0, 47, 110, 105, 120, 47, 115, 116, 111, 114, 101, 47, 115, 111,
+            109, 101, 119, 104, 101, 114, 101, 101, 108, 115,
+            101, // "/nix/store/somewhereelse"
+            1, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 0 // ")"
+        ]
+    );
+    Ok(())
+}
+
+#[tokio::test]
+async fn single_file() -> anyhow::Result<()> {
+    let mut buf: Vec<u8> = vec![];
+    let mut store_client = HelloWorldBlobStoreClient::default();
+
+    write_nar(
+        &mut buf,
+        crate::proto::node::Node::File(FileNode {
+            name: "doesntmatter".to_string(),
+            digest: HELLOWORLD_BLOB_DIGEST.to_vec(),
+            size: HELLOWORLD_BLOB_CONTENTS.len() as u32,
+            executable: false,
+        }),
+        &mut store_client,
+    )
+    .expect("must succeed");
+
+    assert_eq!(
+        buf,
+        vec![
+            13, 0, 0, 0, 0, 0, 0, 0, 110, 105, 120, 45, 97, 114, 99, 104, 105, 118, 101, 45, 49, 0,
+            0, 0, // "nix-archive-1"
+            1, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, // "("
+            4, 0, 0, 0, 0, 0, 0, 0, 116, 121, 112, 101, 0, 0, 0, 0, // "type"
+            7, 0, 0, 0, 0, 0, 0, 0, 114, 101, 103, 117, 108, 97, 114, 0, // "regular"
+            8, 0, 0, 0, 0, 0, 0, 0, 99, 111, 110, 116, 101, 110, 116, 115, // "contents"
+            12, 0, 0, 0, 0, 0, 0, 0, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 0, 0,
+            0, 0, // "Hello World!"
+            1, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 0 // ")"
+        ]
+    );
+
+    Ok(())
+}
+
+#[tokio::test]
+async fn test_complicated() -> anyhow::Result<()> {
+    let mut buf: Vec<u8> = vec![];
+    let mut store_client = SomeDirectoryStoreClient::default();
+
+    write_nar(
+        &mut buf,
+        crate::proto::node::Node::Directory(DirectoryNode {
+            name: "doesntmatter".to_string(),
+            digest: DIRECTORY_COMPLICATED.digest(),
+            size: DIRECTORY_COMPLICATED.size() as u32,
+        }),
+        &mut store_client,
+    )
+    .expect("must succeed");
+
+    assert_eq!(
+        buf,
+        vec![
+            13, 0, 0, 0, 0, 0, 0, 0, 110, 105, 120, 45, 97, 114, 99, 104, 105, 118, 101, 45, 49, 0,
+            0, 0, // "nix-archive-1"
+            1, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, // "("
+            4, 0, 0, 0, 0, 0, 0, 0, 116, 121, 112, 101, 0, 0, 0, 0, // "type"
+            9, 0, 0, 0, 0, 0, 0, 0, 100, 105, 114, 101, 99, 116, 111, 114, 121, 0, 0, 0, 0, 0, 0,
+            0, // "directory"
+            5, 0, 0, 0, 0, 0, 0, 0, 101, 110, 116, 114, 121, 0, 0, 0, // "entry"
+            1, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, // "("
+            4, 0, 0, 0, 0, 0, 0, 0, 110, 97, 109, 101, 0, 0, 0, 0, // "name"
+            5, 0, 0, 0, 0, 0, 0, 0, 46, 107, 101, 101, 112, 0, 0, 0, // ".keep"
+            4, 0, 0, 0, 0, 0, 0, 0, 110, 111, 100, 101, 0, 0, 0, 0, // "node"
+            1, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, // "("
+            4, 0, 0, 0, 0, 0, 0, 0, 116, 121, 112, 101, 0, 0, 0, 0, // "type"
+            7, 0, 0, 0, 0, 0, 0, 0, 114, 101, 103, 117, 108, 97, 114, 0, // "regular"
+            8, 0, 0, 0, 0, 0, 0, 0, 99, 111, 110, 116, 101, 110, 116, 115, 0, 0, 0, 0, 0, 0, 0,
+            0, // "contents"
+            1, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 0, // ")"
+            1, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 0, // ")"
+            5, 0, 0, 0, 0, 0, 0, 0, 101, 110, 116, 114, 121, 0, 0, 0, // "entry"
+            1, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, // "("
+            4, 0, 0, 0, 0, 0, 0, 0, 110, 97, 109, 101, 0, 0, 0, 0, // "name"
+            2, 0, 0, 0, 0, 0, 0, 0, 97, 97, 0, 0, 0, 0, 0, 0, // "aa"
+            4, 0, 0, 0, 0, 0, 0, 0, 110, 111, 100, 101, 0, 0, 0, 0, // "node"
+            1, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, // "("
+            4, 0, 0, 0, 0, 0, 0, 0, 116, 121, 112, 101, 0, 0, 0, 0, // "type"
+            7, 0, 0, 0, 0, 0, 0, 0, 115, 121, 109, 108, 105, 110, 107, 0, // "symlink"
+            6, 0, 0, 0, 0, 0, 0, 0, 116, 97, 114, 103, 101, 116, 0, 0, // "target"
+            24, 0, 0, 0, 0, 0, 0, 0, 47, 110, 105, 120, 47, 115, 116, 111, 114, 101, 47, 115, 111,
+            109, 101, 119, 104, 101, 114, 101, 101, 108, 115,
+            101, //  "/nix/store/somewhereelse"
+            1, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 0, // ")"
+            1, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 0, // ")"
+            5, 0, 0, 0, 0, 0, 0, 0, 101, 110, 116, 114, 121, 0, 0, 0, // "entry"
+            1, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, // "("
+            4, 0, 0, 0, 0, 0, 0, 0, 110, 97, 109, 101, 0, 0, 0, 0, // "name"
+            4, 0, 0, 0, 0, 0, 0, 0, 107, 101, 101, 112, 0, 0, 0, 0, // "keep"
+            4, 0, 0, 0, 0, 0, 0, 0, 110, 111, 100, 101, 0, 0, 0, 0, // "node"
+            1, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, // "("
+            4, 0, 0, 0, 0, 0, 0, 0, 116, 121, 112, 101, 0, 0, 0, 0, // "type"
+            9, 0, 0, 0, 0, 0, 0, 0, 100, 105, 114, 101, 99, 116, 111, 114, 121, 0, 0, 0, 0, 0, 0,
+            0, // "directory"
+            5, 0, 0, 0, 0, 0, 0, 0, 101, 110, 116, 114, 121, 0, 0, 0, // "entry"
+            1, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, // "("
+            4, 0, 0, 0, 0, 0, 0, 0, 110, 97, 109, 101, 0, 0, 0, 0, // "name"
+            5, 0, 0, 0, 0, 0, 0, 0, 46, 107, 101, 101, 112, 0, 0, 0, // ".keep"
+            4, 0, 0, 0, 0, 0, 0, 0, 110, 111, 100, 101, 0, 0, 0, 0, // "node"
+            1, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, // "("
+            4, 0, 0, 0, 0, 0, 0, 0, 116, 121, 112, 101, 0, 0, 0, 0, // "type"
+            7, 0, 0, 0, 0, 0, 0, 0, 114, 101, 103, 117, 108, 97, 114, 0, // "regular"
+            8, 0, 0, 0, 0, 0, 0, 0, 99, 111, 110, 116, 101, 110, 116, 115, 0, 0, 0, 0, 0, 0, 0,
+            0, // "contents"
+            1, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 0, // ")"
+            1, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 0, // ")"
+            1, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 0, // ")"
+            1, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 0, // ")"
+            1, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 0 // ")"
+        ]
+    );
+
+    Ok(())
+}