I have a handler which is executing a store operation on a database using Hibernate Reactive and then uploading a blob to an azure storage container using the synchronous client.

I read I have to wrap all the blocking calls in an executeBlocking() method, so I did so for when I upload a blob. Only problem is that then my tests stop working because the thread is blocked. The test do work when I don’t wrap the call to the blob storage in the executeBlocking() method.

This is the method I have right now:

public Uni<File> downloadSingle(String blobName) {
        return Uni.createFrom().emitter(emitter -> {
            try {
                Path path = Files.createTempDirectory(UUID.randomUUID().toString());

                vertx.executeBlocking(() ->
                                        blobContainerClient.getBlobClient(blobName).downloadToFile(path + "/" + blobName),
                                false
                        )
                        .onComplete(result -> emitter.complete(path.toFile()))
                        .onFailure(emitter::fail);
            } catch (UncheckedIOException | IOException e) {
                emitter.fail(new BlobProblem(
                        new ProblemDetail(
                                "BLOB_DOWNLOAD_PROBLEM",
                                "A problem occurred while download a blob.",
                                Response.Status.INTERNAL_SERVER_ERROR.getStatusCode(),
                                List.of()
                        )
                ));
            }
        });
    }

And this is my test:

    @Test
    @RunOnVertxContext
    void BlobHandlerTest_errorsShouldBeHandledWhenDownloadingABlob() {
        when(blobContainerClient.getBlobClient(any())).thenReturn(blobClient);
        when(blobClient.downloadToFile(any())).thenThrow(new UncheckedIOException(new IOException()));

        blobHandler
                .downloadSingle("blob-name")
                .subscribe()
                .withSubscriber(UniAssertSubscriber.create())
                .awaitSubscription()
                .assertSubscribed()
                .awaitFailure()
                .assertFailed()
                .assertFailedWith(BlobProblem.class);
    }

Does anyone know if I need to do anything different?

PS. I know there’s also an async client for the Azure SDK. Unfortunately I wasn’t able to make that work.