Whether of not you can test for love is immaterial to explaining the experience.
Well, you were asking me to retract this statement based on the theoretical existence of a test:
> Love is a subjective experience of consciousness. We must first have some clue about what consciousness is, then perhaps we will be able to scientifically explain what love is.
Anyhow, I was using it as an example of something that we can't currently test for, not asserting that it will never be testable. So no, I'm not arguing that it will never be testable.
If we do test, however, it will most likely be a test for the brain activity associated with love, not for the actual qualitative feeling of love. As I've said, we know nearly nothing about what subjective experience is despite all we know being subject to it.
Now, it's entirely possible that reasoning about "love" scientifically requires several layers of new language / models on top of the currently established models in neuroscience, which is why I said it's _theoretically_ possible.
In theory, yes. What happens inside your brain isn't untestable or sacred, we're just not there yet technologically (but we'll get there).