Specflow parallel execution of categories [Tags]

Question

I have about 6000 specflow [version 1.9.0.77] tests and those tests are split across 10 categories [tags], roughly 600 test cases per categories and takes about an hour to complete. Currently I’m using Nunit 2.6.4 to execute the tests [executing sequentially] and generating the Specflow flow report out of Nunit test report xml.
I’m planning to move the sequential execution model to parallel execution to reduce the test execution time. There are no static references, no feature or scenario context and test data are unique to test case. I explored Nunit 3.5 with Specflow 2.0 but couldn’t find a solution to run the tests parallel through categories or by tags. Every time it runs sequentially.

I followed the page http://www.specflow.org/documentation/Parallel-Execution/ to setup parallel execution but didn’t worked for me.

Any thoughts?

Answer 1

Two things comes to mind that might go wrong that you don't really mention:

1. To run in parallel, SpecFlow runs Features in parallel. So it doesn't matter how many tags (categories) you use if the are all in the same feature file.

2. Another error source is that to run parallel tests you need at least two processors on the machine running the tests. And if you have a lot of things running, consuming processor power, the number of available processors will decrease to 1 which equal sequential execution of tests.