### Question:
InterpolationMeasure { public static InterpolationMeasure addToLeft(InterpolationMeasure left, InterpolationMeasure right) { checkNotNull(left, "left must not be null"); checkNotNull(right, "right must not be null"); checkArgument(left.dimensions == right.dimensions, "dimensions must be the same"); DiVector.addToLeft(left.distances, right.distances); DiVector.addToLeft(left.measure, right.measure); DiVector.addToLeft(left.probMass, right.probMass); return left; } InterpolationMeasure(int dimensions, int sampleSize);  InterpolationMeasure(InterpolationMeasure base); private  InterpolationMeasure(int sampleSize, DiVector measure, DiVector distances, DiVector probMass); static InterpolationMeasure addToLeft(InterpolationMeasure left, InterpolationMeasure right); static Collector<InterpolationMeasure, InterpolationMeasure, InterpolationMeasure> collector(int dimensions,
            int sampleSize, int numberOfTrees); int getDimensions(); int getSampleSize(); InterpolationMeasure scale(double z); final DiVector measure; final DiVector distances; final DiVector probMass; }### Answer:
@Test public void testAddToLeft() { InterpolationMeasure other1 = new InterpolationMeasure(dimensions, sampleSize); InterpolationMeasure other2 = new InterpolationMeasure(dimensions, sampleSize); for (int i = 0; i < dimensions; i++) { output.probMass.high[i] = 2 * i; output.probMass.low[i] = 2 * i + 1; output.distances.high[i] = 4 * i; output.distances.low[i] = 4 * i + 2; output.measure.high[i] = 6 * i; output.measure.low[i] = 6 * i + 3; other1.probMass.high[i] = other2.probMass.high[i] = 8 * i; other1.distances.high[i] = other2.distances.high[i] = 10 * i; other1.measure.high[i] = other2.measure.high[i] = 12 * i; other1.probMass.low[i] = other2.probMass.low[i] = 8 * i + 4; other1.distances.low[i] = other2.distances.low[i] = 10 * i + 5; other1.measure.low[i] = other2.measure.low[i] = 12 * i + 6; } assertArrayEquals(other1.probMass.high, other2.probMass.high); assertArrayEquals(other1.distances.high, other2.distances.high); assertArrayEquals(other1.measure.high, other2.measure.high); assertArrayEquals(other1.probMass.low, other2.probMass.low); assertArrayEquals(other1.distances.low, other2.distances.low); assertArrayEquals(other1.measure.low, other2.measure.low); InterpolationMeasure.addToLeft(output, other1); for (int i = 0; i < dimensions; i++) { assertEquals(2 * i + 8 * i, output.probMass.high[i]); assertEquals(4 * i + 10 * i, output.distances.high[i]); assertEquals(6 * i + 12 * i, output.measure.high[i]); assertEquals(2 * i + 8 * i + 5, output.probMass.low[i]); assertEquals(4 * i + 10 * i + 7, output.distances.low[i]); assertEquals(6 * i + 12 * i + 9, output.measure.low[i]); } assertArrayEquals(other1.probMass.high, other2.probMass.high); assertArrayEquals(other1.distances.high, other2.distances.high); assertArrayEquals(other1.measure.high, other2.measure.high); assertArrayEquals(other1.probMass.low, other2.probMass.low); assertArrayEquals(other1.distances.low, other2.distances.low); assertArrayEquals(other1.measure.low, other2.measure.low); }