Add test case for default-initialized example

[lukebjerring]

From https://heycam.github.io/webidl/#idl-operations

The following IDL fragment defines an interface with an operation that takes a dictionary argument:

dictionary LookupOptions {
  boolean caseSensitive = false;
};

[Exposed=Window]
interface AddressBook {
  boolean hasAddressForName(USVString name, optional LookupOptions options = {});
};
If hasAddressForName is called with only one argument, the second argument will be a default-initialized LookupOptions dictionary, which will cause caseSensitive to be set to false.

Test case currently fails (expected to, as seems to be the cause of w3c/webref#34)

Not intending to land this PR without the fix, but it's a step in the right direction.

default.json content was generated by temporarily omitting the = {} syntax, and JSON.stringify'ing the AST.

[saschanaz]

Hi, thank you for the PR!

default.json content was generated by temporarily omitting the = {} syntax, and JSON.stringify'ing the AST.

I think this is why the test is failing, could you explain the reason you did it?

And I'm not sure why we need another test as #338 added one with = {}.

[lukebjerring]

Well, for one, it's a different context; the test in #338 is a member with default value, not a default value of a parameter to an operator.

The AST fails to generate at all with the = {} present, so I omitted it to generate at least something (to fill the json file). The failure mode for this test is not just a missing default, it's that the whole tree is missing.

Sorry if this reply is sloppy, I'm on my phone :)

[lukebjerring]

In case it's not clear in the description:
See w3c/webref#34 for how this is manifesting problematically in a real-world application.

[saschanaz]

Well, for one, it's a different context; the test in #338 is a member with default value, not a default value of a parameter to an operator.

Ah, definitely worth then 👍

The AST fails to generate at all with the = {} present, so I omitted it to generate at least something (to fill the json file). The failure mode for this test is not just a missing default, it's that the whole tree is missing.

What did you do to generate AST? npm run acquire (after running npm run build) should autogenerate the JSON file, and I see it correctly generates an AST as expected. I'll push the result so that you can check it.

@marcoscaceres Do you have an idea why Travis is failing to start again? I thought the migration to service to app fixed it, but seems not 🤔

PS: The wierd g {} problem when doing npm run acquire should be removed by #369.

[marcoscaceres]

Having a look at Travis...

[marcoscaceres]

Hmm... I don't have rights to access the settings... but what's more strange is that the other PRs are all fine.

[saschanaz]

I think Travis has a problem only with PRs from forks.

[marcoscaceres]

Yeah, I was thinking the same... maybe just merge and hope for the best 🙊😂

[lukebjerring]

Thanks!