irfft throws instead of segfaults on scalars (#2109)

python/tests/test_fft.py

@@ -194,6 +194,11 @@ class TestFFT(mlx_tests.MLXTestCase):
         r_np = np.fft.ifft(segment, n=n_fft)
         self.assertTrue(np.allclose(r, r_np, atol=1e-5, rtol=1e-5))
 
+    def test_fft_throws(self):
+        x = mx.array(3.0)
+        with self.assertRaises(ValueError):
+            mx.fft.irfftn(x)
+
 
 if __name__ == "__main__":
     unittest.main()