Add test case for undefined method args

It Vue it is possible to define methods which directly calls another method.

Examples

methods: {
  someMethod: MethodThatReturnAFunction(),
}

OR

methods: {
  someMethod: CallsSomeOtherMethod,
}

Explanation

In that case the method would have parameters, so hasParams would pass, but method.args would be undefined. I added a check which simply sets args to a blank string "" if method.args is null.

Use Case

methods: {
  calledVeryOften: functionsThatReturnsADebouncedFunction(),
}