Consider publishing test-jar

[Walliee]

I was looking to stub SchemaRegistryClient and stumbled across StubSchemaRegistryClient.

I think this would be nice to share with spring-cloud-schema-registry consumers for easier testing. Not sure if there are other sharable test utilities in the test folder.

Alternatively, an in-memory SchemaRegistryClient could be added to the main jar.

[nhomble]

I'd be interested in this although I would point out that the name of the class is misleading. It's under their avro package and assumes avro schemas

		if (!AvroSchemaRegistryClientMessageConverter.AVRO_FORMAT
				.equals(schemaReference.getFormat())) {
			throw new IllegalArgumentException("Only 'avro' is supported by this client");
		}