Adapter Testkit

Inference.Testkit.AdapterCase provides small conformance helpers for adapter tests.

The helpers are normal library functions. They do not require ExUnit at runtime and can be called from ExUnit tests in adapter-owning projects.

Example:

defmodule MyAdapterTest do
  use ExUnit.Case, async: true

  alias Inference.Testkit.AdapterCase

  test "adapter returns text" do
    response =
      AdapterCase.assert_text_completion(MyAdapter,
        adapter_opts: [fake_backend: MyFakeBackend]
      )

    assert response.text != ""
  end
end

The testkit covers:

• successful text completion;
• provider error normalization;
• the response-format contract — for every member of the closed union the adapter must map it or refuse it with :response_format_unsupported;
• capability reporting — every reported Inference.Capability is well formed, names are unique, and :require names must be reported;
• unsupported stream behavior;
• metadata redaction;
• trace metadata redaction.

AdapterCase.assert_response_format_contract(MyAdapter,
  adapter_opts: [fake_backend: MyFakeBackend]
)

AdapterCase.assert_capability_contract(MyAdapter,
  require: [:response_format_json_schema, :tools]
)

Default tests should use fake provider modules. Live provider tests belong in explicitly gated examples or smoke-test suites.

Adapter-owning projects should add their own tests for option precedence and response-field preservation when they depend on adapter-specific options. The shared testkit is a floor, not proof that a governed adapter preserved every downstream contract field.