throw Error if file not found

[jtlapp]

No exception was being thrown when a specified .ts file was not found. This PR throws the exception. It includes tests for .ts file not found and tsconfig.json not found.

The Typescript compiler does of course detect that the .ts was not found, and it reports it in diagnostics. I spent more time than I should have trying to figure out how to pull the error out of diagnostics without also pulling out the errors that would be handled in later code.

So I opted to just throw an fs.existsSync(file) in there. Easy peasy, done.

Thanks for this awesome tool. I can't believe that its use isn't mandatory for all typings!

[jtlapp]

I'm noticing something strange. Your double quoted strings were converted to single quoted strings. I ran the linter, wonder if it did that.

Yeah, had to be the linter. There's also some reformatting.

[aikoven]

Thanks!

I'll make a release shortly.

The reformatting is probably due to Prettier or something alike embedded in your editor.

[aikoven]

Just published typings-tester@0.3.1.