### Question:
InitialStateCalculator { public double[] growSignal(double[] signal) { return growSignal(signal, false); } InitialStateCalculator(FilterCoefficients filterCoefficients); double[] getInitialState(); double[] growSignal(double[] signal); double[] growSignal(double[] signal, boolean leftOnly);  }### Answer:
@Test public void testGrowSignal() { double[] signal = new double[20]; for (int i = 0; i < 20; i++) { signal[i] = i + 1; } InitialStateCalculator calculator = new InitialStateCalculator(getSampleFilterCoefficients1()); double[] grownSignal = calculator.growSignal(signal); double[] expected = new double[] {-11, -10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32 }; assertArrayEquals(expected, grownSignal, 1e-4); }