1 files changed, 253 insertions, 0 deletions
diff --git a/tvix/castore/src/blobservice/tests/mod.rs b/tvix/castore/src/blobservice/tests/mod.rs
new file mode 100644
index 000000000000..b1ae66bac40d
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+++ b/tvix/castore/src/blobservice/tests/mod.rs
@@ -0,0 +1,253 @@
+//! This contains test scenarios that a given [BlobService] needs to pass.
+//! We use [rstest] and [rstest_reuse] to provide all services we want to test
+//! against, and then apply this template to all test functions.
+
+use rstest::*;
+use rstest_reuse::{self, *};
+use std::io;
+use tokio::io::AsyncReadExt;
+use tokio::io::AsyncSeekExt;
+
+use super::BlobService;
+use crate::blobservice;
+use crate::fixtures::BLOB_A;
+use crate::fixtures::BLOB_A_DIGEST;
+use crate::fixtures::BLOB_B;
+use crate::fixtures::BLOB_B_DIGEST;
+
+mod utils;
+use self::utils::make_grpc_blob_service_client;
+
+/// This produces a template, which will be applied to all individual test functions.
+/// See https://github.com/la10736/rstest/issues/130#issuecomment-968864832
+#[template]
+#[rstest]
+#[case::memory(blobservice::from_addr("memory://").await.unwrap())]
+#[case::grpc(make_grpc_blob_service_client().await)]
+#[case::sled(blobservice::from_addr("sled://").await.unwrap())]
+pub fn blob_services(#[case] blob_service: impl BlobService) {}
+
+/// Using [BlobService::has] on a non-existing blob should return false.
+#[apply(blob_services)]
+#[tokio::test]
+async fn has_nonexistent_false(blob_service: impl BlobService) {
+    assert!(!blob_service
+        .has(&BLOB_A_DIGEST)
+        .await
+        .expect("must not fail"));
+}
+
+/// Using [BlobService::chunks] on a non-existing blob should return Ok(None)
+#[apply(blob_services)]
+#[tokio::test]
+async fn chunks_nonexistent_false(blob_service: impl BlobService) {
+    assert!(blob_service
+        .chunks(&BLOB_A_DIGEST)
+        .await
+        .expect("must be ok")
+        .is_none());
+}
+
+// TODO: do tests with `chunks`
+
+/// Trying to read a non-existing blob should return a None instead of a reader.
+#[apply(blob_services)]
+#[tokio::test]
+async fn not_found_read(blob_service: impl BlobService) {
+    assert!(blob_service
+        .open_read(&BLOB_A_DIGEST)
+        .await
+        .expect("must not fail")
+        .is_none())
+}
+
+/// Put a blob in the store, check has, get it back.
+#[apply(blob_services)]
+// #[case::small(&fixtures::BLOB_A, &fixtures::BLOB_A_DIGEST)]
+// #[case::big(&fixtures::BLOB_B, &fixtures::BLOB_B_DIGEST)]
+#[tokio::test]
+async fn put_has_get(blob_service: impl BlobService) {
+    // TODO: figure out how to instantiate this with BLOB_A and BLOB_B, as two separate cases
+    for (blob_contents, blob_digest) in &[
+        (&*BLOB_A, BLOB_A_DIGEST.clone()),
+        (&*BLOB_B, BLOB_B_DIGEST.clone()),
+    ] {
+        let mut w = blob_service.open_write().await;
+
+        let l = tokio::io::copy(&mut io::Cursor::new(blob_contents), &mut w)
+            .await
+            .expect("copy must succeed");
+        assert_eq!(
+            blob_contents.len(),
+            l as usize,
+            "written bytes must match blob length"
+        );
+
+        let digest = w.close().await.expect("close must succeed");
+
+        assert_eq!(*blob_digest, digest, "returned digest must be correct");
+
+        assert!(
+            blob_service.has(blob_digest).await.expect("must not fail"),
+            "blob service should now have the blob"
+        );
+
+        let mut r = blob_service
+            .open_read(blob_digest)
+            .await
+            .expect("open_read must succeed")
+            .expect("must be some");
+
+        let mut buf: Vec<u8> = Vec::new();
+        let mut pinned_reader = std::pin::pin!(r);
+        let l = tokio::io::copy(&mut pinned_reader, &mut buf)
+            .await
+            .expect("copy must succeed");
+
+        assert_eq!(
+            blob_contents.len(),
+            l as usize,
+            "read bytes must match blob length"
+        );
+
+        assert_eq!(&blob_contents[..], &buf, "read blob contents must match");
+    }
+}
+
+/// Put a blob in the store, and seek inside it a bit.
+#[apply(blob_services)]
+#[tokio::test]
+async fn put_seek(blob_service: impl BlobService) {
+    let mut w = blob_service.open_write().await;
+
+    tokio::io::copy(&mut io::Cursor::new(&BLOB_B.to_vec()), &mut w)
+        .await
+        .expect("copy must succeed");
+    w.close().await.expect("close must succeed");
+
+    // open a blob for reading
+    let mut r = blob_service
+        .open_read(&BLOB_B_DIGEST)
+        .await
+        .expect("open_read must succeed")
+        .expect("must be some");
+
+    let mut pos: u64 = 0;
+
+    // read the first 10 bytes, they must match the data in the fixture.
+    {
+        let mut buf = [0; 10];
+        r.read_exact(&mut buf).await.expect("must succeed");
+
+        assert_eq!(
+            &BLOB_B[pos as usize..pos as usize + buf.len()],
+            buf,
+            "expected first 10 bytes to match"
+        );
+
+        pos += buf.len() as u64;
+    }
+    // seek by 0 bytes, using SeekFrom::Start.
+    let p = r
+        .seek(io::SeekFrom::Start(pos))
+        .await
+        .expect("must not fail");
+    assert_eq!(pos, p);
+
+    // read the next 10 bytes, they must match the data in the fixture.
+    {
+        let mut buf = [0; 10];
+        r.read_exact(&mut buf).await.expect("must succeed");
+
+        assert_eq!(
+            &BLOB_B[pos as usize..pos as usize + buf.len()],
+            buf,
+            "expected data to match"
+        );
+
+        pos += buf.len() as u64;
+    }
+
+    // seek by 5 bytes, using SeekFrom::Start.
+    let p = r
+        .seek(io::SeekFrom::Start(pos + 5))
+        .await
+        .expect("must not fail");
+    pos += 5;
+    assert_eq!(pos, p);
+
+    // read the next 10 bytes, they must match the data in the fixture.
+    {
+        let mut buf = [0; 10];
+        r.read_exact(&mut buf).await.expect("must succeed");
+
+        assert_eq!(
+            &BLOB_B[pos as usize..pos as usize + buf.len()],
+            buf,
+            "expected data to match"
+        );
+
+        pos += buf.len() as u64;
+    }
+
+    // seek by 12345 bytes, using SeekFrom::
+    let p = r
+        .seek(io::SeekFrom::Current(12345))
+        .await
+        .expect("must not fail");
+    pos += 12345;
+    assert_eq!(pos, p);
+
+    // read the next 10 bytes, they must match the data in the fixture.
+    {
+        let mut buf = [0; 10];
+        r.read_exact(&mut buf).await.expect("must succeed");
+
+        assert_eq!(
+            &BLOB_B[pos as usize..pos as usize + buf.len()],
+            buf,
+            "expected data to match"
+        );
+
+        #[allow(unused_assignments)]
+        {
+            pos += buf.len() as u64;
+        }
+    }
+
+    // seeking to the end is okay…
+    let p = r
+        .seek(io::SeekFrom::Start(BLOB_B.len() as u64))
+        .await
+        .expect("must not fail");
+    pos = BLOB_B.len() as u64;
+    assert_eq!(pos, p);
+
+    {
+        // but it returns no more data.
+        let mut buf: Vec<u8> = Vec::new();
+        r.read_to_end(&mut buf).await.expect("must not fail");
+        assert!(buf.is_empty(), "expected no more data to be read");
+    }
+
+    // seeking past the end…
+    // should either be ok, but then return 0 bytes.
+    // this matches the behaviour or a Cursor<Vec<u8>>.
+    if let Ok(_pos) = r.seek(io::SeekFrom::Start(BLOB_B.len() as u64 + 1)).await {
+        let mut buf: Vec<u8> = Vec::new();
+        r.read_to_end(&mut buf).await.expect("must not fail");
+        assert!(buf.is_empty(), "expected no more data to be read");
+    }
+    // or not be okay.
+
+    // TODO: this is only broken for the gRPC version
+    // We expect seeking backwards or relative to the end to fail.
+    // r.seek(io::SeekFrom::Current(-1))
+    //     .expect_err("SeekFrom::Current(-1) expected to fail");
+
+    // r.seek(io::SeekFrom::Start(pos - 1))
+    //     .expect_err("SeekFrom::Start(pos-1) expected to fail");
+
+    // r.seek(io::SeekFrom::End(0))
+    //     .expect_err("SeekFrom::End(_) expected to fail");
+}