import pytest
import torch
import torch.nn.functional as F
from sgl_kernel import dsv3_router_gemm


@pytest.mark.parametrize("num_tokens", [i + 1 for i in range(16)])
def test_dsv3_router_gemm(num_tokens):
    num_experts = 256
    hidden_dim = 7168

    mat_a = torch.randn(
        (num_tokens, hidden_dim), dtype=torch.bfloat16, device="cuda"
    ).contiguous()
    mat_b = torch.randn(
        (num_experts, hidden_dim), dtype=torch.bfloat16, device="cuda"
    ).contiguous()
    output = torch.empty(
        (num_tokens, num_experts), dtype=torch.float32, device="cuda"
    ).contiguous()

    ref = F.linear(mat_a, mat_b).to(torch.float32)

    output = dsv3_router_gemm(mat_a, mat_b)

    assert torch.allclose(
        output, ref, rtol=1e-2, atol=1e-3
    ), "Router GEMM output mismatch with torch.nn.functional.linear reference"


if __name__ == "__main__":
    pytest.main([__file__])