Flaky test

[rossta]

Describe the bug

When I run rspec with a specific seed, the suite fails on the page_embedding_spec.rb:

$ bin/rspec --seed 52318 --fail-fast

Randomized with seed 52318
.........................................................................................................................................F

Failures:

  1) PageEmbedding serializes and deserializes embedding vector
     Failure/Error: ActiveSupport::JSON.decode(value)
     
     JSON::ParserError:
       unexpected token at '_?;?)?????p'
     # /.gem/ruby/3.3.5/gems/json-2.9.0/lib/json/common.rb:221:in `parse'
     # /.gem/ruby/3.3.5/gems/json-2.9.0/lib/json/common.rb:221:in `parse'
     # ./app/models/types/vector.rb:16:in `deserialize'
     # ./spec/models/page_embedding_spec.rb:18:in `block (2 levels) in <top (required)>'
     # ./spec/support/webmock_vcr.rb:40:in `block (3 levels) in <top (required)>'
     # /.gem/ruby/3.3.5/gems/vcr-6.3.1/lib/vcr.rb:274:in `turned_off'
     # ./spec/support/webmock_vcr.rb:40:in `block (2 levels) in <top (required)>'
     # /.gem/ruby/3.3.5/gems/webmock-3.24.0/lib/webmock/rspec.rb:39:in `block (2 levels) in <top (required)>'

Finished in 11.12 seconds (files took 3.88 seconds to load)
138 examples, 1 failure

Failed examples:

rspec ./spec/models/page_embedding_spec.rb:8 # PageEmbedding serializes and deserializes embedding vector

Randomized with seed 52318

I can reproduce locally. This has happened at least once in CI: https://github.com/joyofrails/joyofrails.com/actions/runs/12402409885/job/34623858417

The test typically passed otherwise.

The :random_embedding factory most certainly plays a role.