Merge pull request wuchong#1 from DiegoReiriz/patch-1

Added a tests section

Author: wuchong

README.md

@@ -12,6 +12,7 @@ A curated list of awesome things related to Apache Flink. Inspired by [Awesome H
   - [Interfaces](#interfaces)
   - [Connectors](#connectors)
   - [Benchmarks](#benchmarks)
+  - [Tests](#Tests)
 - [Resources](#resources)
     - [Official Resources](#official-resources)
     - [External Resources](#external-resources)
@@ -47,6 +48,9 @@ A curated list of awesome things related to Apache Flink. Inspired by [Awesome H
 - [Yahoo! Streaming benchmark](https://github.com/yahoo/streaming-benchmarks)
 - [Yahoo! Streaming benchmark extension](https://github.com/dataArtisans/yahoo-streaming-benchmark)
 
+## Tests
+- [Flinnk spector](https://github.com/ottogroup/flink-spector) - provides a framework to define unit tests for Apache Flink data flows. The framework executes data flows locally and verifies the output using predefined expectations.
+
 # Resources
 Various resources, such as books, websites and articles.