fix(OpenAI): Add usage support to streamed completions (#708)

* Feat: Add usage to streamed completions

* run lint

---------

Co-authored-by: Mathias Rasmussen <mra@ordbogen.com>

Author: math625f

src/Responses/Completions/CreateStreamedResponse.php

@@ -28,6 +28,7 @@ private function __construct(
         public readonly string $object,
         public readonly int $created,
         public readonly string $model,
+        public readonly ?CreateResponseUsage $usage,
         public readonly array $choices,
     ) {}
 
@@ -47,6 +48,7 @@ public static function from(array $attributes): self
             $attributes['object'],
             $attributes['created'],
             $attributes['model'],
+            isset($attributes['usage']) ? CreateResponseUsage::from($attributes['usage']) : null,
             $choices,
         );
     }
@@ -65,6 +67,7 @@ public function toArray(): array
                 static fn (CreateResponseChoice $result): array => $result->toArray(),
                 $this->choices,
             ),
+            'usage' => $this->usage?->toArray(),
         ];
     }
 }

tests/Fixtures/Streams/CompletionCreate.txt

@@ -7,5 +7,5 @@ data: {"id": "cmpl-6wcyFqMKXiZffiydSfWHhjcgsf3KD", "object": "text_completion",
 data: {"id": "cmpl-6wcyFqMKXiZffiydSfWHhjcgsf3KD", "object": "text_completion", "created": 1679430847, "choices": [{"text": " wanted", "index": 0, "logprobs": null, "finish_reason": null}], "model": "gpt-3.5-turbo-instruct"}
 data: {"id": "cmpl-6wcyFqMKXiZffiydSfWHhjcgsf3KD", "object": "text_completion", "created": 1679430847, "choices": [{"text": " to", "index": 0, "logprobs": null, "finish_reason": null}], "model": "gpt-3.5-turbo-instruct"}
 data: {"id": "cmpl-6wcyFqMKXiZffiydSfWHhjcgsf3KD", "object": "text_completion", "created": 1679430847, "choices": [{"text": " check", "index": 0, "logprobs": null, "finish_reason": null}], "model": "gpt-3.5-turbo-instruct"}
-data: {"id": "cmpl-6wcyFqMKXiZffiydSfWHhjcgsf3KD", "object": "text_completion", "created": 1679430847, "choices": [{"text": " in", "index": 0, "logprobs": null, "finish_reason": "length"}], "model": "gpt-3.5-turbo-instruct"}
+data: {"id": "cmpl-6wcyFqMKXiZffiydSfWHhjcgsf3KD", "object": "text_completion", "created": 1679430847, "choices": [{"text": " in", "index": 0, "logprobs": null, "finish_reason": "length"}], "model": "gpt-3.5-turbo-instruct", "usage": {"prompt_tokens": 1, "completion_tokens": 16, "total_tokens": 17}}
 data: [DONE]

tests/Resources/Completions.php

@@ -94,6 +94,11 @@
         ->logprobs->toBe(null)
         ->finishReason->toBeNull();
 
+    $iterator = iterator_to_array($result->getIterator());
+    $last = end($iterator);
+    expect($last->usage)
+        ->toBeInstanceOf(CreateResponseUsage::class);
+
     expect($result->meta())
         ->toBeInstanceOf(MetaInformation::class);
 });