Improve tests

[wwerner]

Hey again,

I'd love to swap out the hand-rolled unit test solution for a framework.
Drivers:

• Tests use external systems (e.g. ifconfig.me, httpbin.org), so they depend on those services to be up and available
• It's hard to track coverage
• Adding tests is a bit cumbersome, at some point the test file will grow large, then we'll need to regorganize tests anyway.
• Tests rely on curl to be installed locally. This might not be the case by default when building in containers. I also had issues w/ a different curl version.

I've tried with Jest in my (very WIP) TS port.
Here's the gist of it:

• Instead of targeting external systems, the tests spin up a tiny local express app that basically returns the received HTTP messages. See here.
• Use a utility function to make requests against this app through the proxy using plain node http: https://github.com/wwerner/transparent-proxy/pull/2/files#diff-8951d3f508f54ec05c5df49f04f821a2aec5c75bce858639461f388e498a398cR10
• Tests then spin up a configured proxy, make a request and assert the results: https://github.com/wwerner/transparent-proxy/pull/2/files#diff-05d1e5650843d2a077ab7636ce95d7af53569eb7322319940c67fd5d89fe71a9R4
• Jest allows for measuring coverage, is well supported, provides mocking primitives and nicely extensible with custom matchers, should we want to.

I could help switch the existing tests over.
What do you think?

[gr3p1p3]

Yess! I thought multiple times about the use of curl and refactoring the test.js file that is growing slowly up.
I'm not confidential with jest, but I can learn :)

Thanks for this! Let's do it!

[wwerner]

I pushed a scaffold for testing and one initial test here: #31

This is what a test will look like in the new structure: https://github.com/gr3p1p3/transparent-proxy/pull/31/files#diff-3a306758c1d18927d16b133c9fc27dae8661649521e55023f03ce846974bc275R4

I'll continue working on porting the rest of the tests.

@leppert: I'm still unsure whether I want to maintain a fork. Until we've decided, I'll continue contributing here.