tests/test_api.py

"""tests/test_api.py — FastAPI endpoint integration tests."""
from __future__ import annotations

import io
import pytest
import numpy as np
from PIL import Image
from fastapi.testclient import TestClient


@pytest.fixture(scope="module")
def client():
    from src.api.main import app
    return TestClient(app)


@pytest.fixture
def jpeg_bytes():
    arr = (np.random.rand(224, 224, 3) * 255).astype(np.uint8)
    buf = io.BytesIO()
    Image.fromarray(arr).save(buf, format="JPEG")
    return buf.getvalue()


# ── GET /health ───────────────────────────────────────────────────────────────

def test_health_returns_200(client):
    r = client.get("/health")
    assert r.status_code == 200


def test_health_has_required_fields(client):
    data = client.get("/health").json()
    assert data["status"] == "ok"
    assert "version" in data
    assert "engines" in data
    assert "inference_backend" in data
    assert "runpod_configured" in data
    assert set(data["engines"]) == {"fingerprint", "coherence", "sstgnn"}


def test_health_models_returns_inventory(client):
    data = client.get("/health/models").json()
    assert "fingerprint" in data
    assert "coherence" in data
    assert "sstgnn" in data
    assert "generator_labels" in data
    assert "stable_diffusion" in data["generator_labels"]


# ── GET / ─────────────────────────────────────────────────────────────────────

def test_root_returns_html(client):
    r = client.get("/")
    assert r.status_code == 200
    assert "text/html" in r.headers["content-type"]


# ── POST /detect/image ────────────────────────────────────────────────────────

def test_detect_image_returns_200(client, jpeg_bytes):
    r = client.post(
        "/detect/image",
        files={"file": ("test.jpg", jpeg_bytes, "image/jpeg")},
    )
    assert r.status_code == 200


def test_detect_image_response_schema(client, jpeg_bytes):
    data = client.post(
        "/detect/image",
        files={"file": ("test.jpg", jpeg_bytes, "image/jpeg")},
    ).json()

    assert data["verdict"] in ("FAKE", "REAL")
    assert 0.0 <= data["confidence"] <= 1.0
    assert "attributed_generator" in data
    assert "explanation" in data
    assert "engine_breakdown" in data
    assert len(data["engine_breakdown"]) == 3


def test_detect_image_engine_names(client, jpeg_bytes):
    data = client.post(
        "/detect/image",
        files={"file": ("test.jpg", jpeg_bytes, "image/jpeg")},
    ).json()

    engine_names = {e["engine"] for e in data["engine_breakdown"]}
    assert engine_names == {"fingerprint", "coherence", "sstgnn"}


def test_detect_image_engine_confidence_range(client, jpeg_bytes):
    data = client.post(
        "/detect/image",
        files={"file": ("test.jpg", jpeg_bytes, "image/jpeg")},
    ).json()

    for engine in data["engine_breakdown"]:
        assert 0.0 <= engine["confidence"] <= 1.0
        assert engine["verdict"] in ("FAKE", "REAL")


def test_detect_image_too_large_returns_413(client):
    big = b"x" * (21 * 1024 * 1024)  # 21MB > 20MB limit
    r   = client.post(
        "/detect/image",
        files={"file": ("big.jpg", big, "image/jpeg")},
    )
    assert r.status_code == 413


def test_detect_image_wrong_type_returns_415(client, jpeg_bytes):
    r = client.post(
        "/detect/image",
        files={"file": ("test.mp4", jpeg_bytes, "video/mp4")},
    )
    assert r.status_code == 415


def test_detect_image_processing_time_positive(client, jpeg_bytes):
    data = client.post(
        "/detect/image",
        files={"file": ("test.jpg", jpeg_bytes, "image/jpeg")},
    ).json()
    assert data["processing_time_ms"] >= 0


# ── POST /detect/video ────────────────────────────────────────────────────────

def test_detect_video_wrong_type_returns_415(client, jpeg_bytes):
    r = client.post(
        "/detect/video",
        files={"file": ("test.jpg", jpeg_bytes, "image/jpeg")},
    )
    assert r.status_code == 415