#4: add resources

[ForNeVeR]

Architectural solution

1. We'll have two additional assemblies: Nightwatch.Core and Nightwatch.Resources.
   • Nightwatch.Core is a common assembly that's intended to be used by all the (potentially third-party) Resource libraries
   • Nightwatch.Resources is a default Resource assembly (should be optional ideally)
2. Each of the resource types should have its' ResourceFactory definition that builds the checker function from the parameters passed from the configuration.
3. Program module loads the default Resources from the Nightwatch.Resources. Later we could wire up additional used-supplied Resource assemblies there.

Resource configuration

For now, I've decided to implement two Resource types:

• type: http that will send HTTP GET requests and examine the return codes
• type: shell that will execute shell commands and examine the processes' exit codes

When authoring the configuration, user should explicitly state type: xxx in each of the configuration files.

Each Resource could have its own parameter set, defined by param: configuration attribute. That'll be a simple key-value map parsed by the Resource factories.

There're sample configuration files for each resource type in the samples directory.

Remaining work

• [x] fix all the TODOs
• [x] fix the tests (YAML parser isn't working for Map<_, _>)
• [x] write the documentation for each Resource type
• [x] write the contributor documentation (e.g. "How to add my own Resource")
• [x] write additional tests for both the new Resource types
• [x] add an issue about plugin loading (probably partially based on this PR's description): #14
• [x] make sure the solution is C#-compatible
  • [x] replace param : Map<_, _> with param : IDictionary<_, >
  • [x] remove Async from resource factory interface
  • [x] make a sample C# resource to test the compatibility
• [x] make sure to remove non-public parts from the Nightwatch.Core assembly
• [x] make sure the code is not a mess
• [x] when performing a final review, make sure all the new logic is properly covered by tests

Impact

Closes #4.

[ForNeVeR]

@gsomix wanna review?

[gsomix]

@ForNeVeR Yes.

[ForNeVeR]

Thanks for the review!