fix local web test and remove simulation.json

[tylerflex]

No description provided.

[momchil-flex]

Question I had on slack: what I'm confused about is also why we need the line that explicitly saves the batch in the test? didn't we have something where the batch is saved to file directly when creating?

[tylerflex]

ok I think I know what’s going on with the batchdata test.
https://github.com/flexcompute/tidy3d/blob/develop/tests/_test_local/_test_web.py#L258-L263
It’s a bit confusing:

1. the test has @clear_tmp on it for some reason, so basically the tmp directory is totally wiped before the test is run.
2. the test then grabs the Batch object and tries to download a file of the batch to tmp. (Note: previously, this was a .json format, but now it only works if .hdf5 , i’ll explain why).
3. BatchData.load() is then called, which looks for a _batch_path in the tmp directory. https://github.com/flexcompute/tidy3d/blob/develop/tidy3d/web/container.py#L199-L217
4. Batch._batch_path used to be path + batch.json but now it’s path + batch.hdf5 so this part simply failed before because the test was saving a .json file and looking for a .hdf5 file.

however, we were confused earlier because the test seemed to fail if the batch was not written to file in the test. The reason is because of the first bullet point. Basically clear_tmp wiped the directory so we needed to save some batch file in there before the BatchData can be loaded from path. So:

• To fix the test:
  • We can either leave the to_file() with .hdf5 format (current commit)
  • or we can simply not clear_tmp after the previous test is done, which I verified also works.
• We might also want to consider changing how BatchData loads, perhaps by providing a @classmethod to load it from an existing Batch instance? pretty low priority for now i think though.