Workflows Community is inviting you to a meetup focused on supercharging your Nextflow pipelines with Groovy.

  1. Sateesh Peri (nf-core) will do a hands-on exploration of nf-test, a simple test framework specifically tailored for Nextflow pipelines. This presentation will delve into:
    • Structure and Implementation: Discover nf-test's intuitive Groovy-based structure using 'when' and 'then' blocks, which simplifies the definition of input parameters and expected outputs compared to pytest-workflow's YAML-based approach.
    • Test Case Organization: Learn about nf-test's ability to consolidate a suite of tests within a single file, enabling more efficient test management and maintenance.
    • Assertions and Checks: Uncover different types of assertions available for tests and compatibility with third-party libraries for creating specific assertions.
    • Snapshot Support: Understand the benefits of nf-test's snapshot functionality, which allows for easier comparisons of actual and expected outputs.


  1. Simon Murray (Wellcome Sanger Institute) will talk about integrating groovy functions and operators in Nextflow pipelines.
    • What is a ternary operator and why is it useful?
    • How to write your own error and help functions?
    • How to determine memory size based on input parameters and formulas?
    • How to generate a unique timestamp variable?