from fastapi.testclient import TestClient

from app.main import app


def test_preview_endpoint_success():
    client = TestClient(app)
    payload = {
        "template_content": "ok {trans_amt}",
        "sample_payload": {"trans_amt": 123}
    }
    resp = client.post("/admin/templates/preview", json=payload)
    assert resp.status_code == 200
    assert resp.json().get("rendered") == "ok 123"


def test_preview_endpoint_strict_failure():
    client = TestClient(app)
    # Template refers to undefined variable -> StrictUndefined should cause error -> 400
    payload = {"template_content": "{{ undefined_var }}", "sample_payload": {}}
    resp = client.post("/admin/templates/preview", json=payload)
    assert resp.status_code == 400