In that case could you explain how the output tensor corresponds to y_test?
y_train_pred has a shape of [1, 24] and seems to contain probabilities. Based on this I assume you are working with a single sample and 24 classes.
Is y_test the one-hot encoded target tensor corresponding to this output?
If so, then the prediction for this particular sample is correct:
torch.argmax(y, dim=1) == torch.argmax(x, dim=1)
> tensor([True])

and you shouldn’t get a 0 accuracy.