According to the way things are defined, a theory is 'scientific' or not—not the test. So if one can devise a test that can falsify a prediction of the theory, then the theory is scientific.
If it is impossible right now to create such a practical test then, no, the theory is not scientific. If you can't actually perform any kind of test (for whatever reason), there's no way to get falsifying information, and so the theory cannot be falsified and so is not 'scientific'.
But a theory that has impractical tests is much more in the direction of science than something without even the possibility of falsifiability with unlimited resources. It eventually may allow falsification. Also, one's falsification test may have its own problems (one has a subsidiary theory about how the test works), and it may take engineering of that subsidiary theory which will then enable it to falsify the main theory.