Make tests work without input/output files

[phillipskevin]

It would be really nice if we could just use template literals for tests, instead of requiring new files for every test and updates to the transforms file:

can-migrate/build/transforms.json

Lines 10 to 21 in 4d40248

	{
	"input": "can-component-rename/input.js",
	"outputPath": "can-component-rename/can-component-rename-input.js",
	"type": "fixture",
	"version": "3"
	},
	{
	"input": "can-component-rename/output.js",
	"outputPath": "can-component-rename/can-component-rename-output.js",
	"type": "fixture",
	"version": "3"
	},

It would be nice if you could just do something like

runTests("can-stache/console-log", [{
  in: `
    {{log}}
  `,
  out: `
    {{console.log(this)}}
  `
}, {
  in: `
    {{log(foo)}}
  `,
  out: `
    {{console.log(foo)}}
  `
}];

This would make it much easier to add new tests and would make it more likely for people to add new tests.

[Mattchewone]

Looking over the repo and want to make some notes on what is happening:

• Files are written in src
• Generate compiles/babelises the source and outputs to lib
• Tests are copied into the lib alongside the transform
• Test input/outputs are copied into fixtures
• Tests file requires are added to the test/test.js file for mocha to run

If we are to remove the extra in/out files in favour of writing them inline within the test file, we would need to remove the step to move these files into fixtures.
We would need to pull the content and put it into a method that would run the transform with the in/out source being the content. The diffFiles util would need to be modified with one that would read the source in/out from a string as opposed to reading from a file.