Image-sequencer: Blob detection module needs a test

[jywarren]

We have an amazing OpenCV based blob detection module @aashna27 created: #1185

~Strangely it's not in the demo or the beta: https://sequencer.publiclab.org/examples/ https://beta.sequencer.publiclab.org/examples/~

~Though it definitely works in Aashna's demo: https://aashna27.github.io/image-sequencer/examples/#steps=brightness{},brightness{},blob-analysis{}~

~@aashna27 are you able to take a look to see how it got removed?~

We should add a test like this one to protect it!

https://github.com/publiclab/image-sequencer/blob/89fb3585ac082c6bce3cd72640ec2be9f75df5f0/test/core/modules/colorbar.js

Let's protect it! It's a very powerful feature 😄

[jywarren]

False alarm! needed to clear cache on an old browser.

https://sequencer.publiclab.org/examples/#steps=brightness{},brightness{},blob-analysis{} this works!

Changing title to be "write test for this module"

[blurry-x-face]

I'll be happy to write the test for it!

[blurry-x-face]

But I was having problem in running it in node, I'll try to solve that issue first!

[jywarren]

Thank you!!

[blurry-x-face]

@jywarren PR to make it work on Node #1589, please have a look!