[query] Implemented the Graphite integralByInterval function

src/query/graphite/native/builtin_functions_test.go

@@ -685,6 +685,23 @@ func TestMovingAverageError(t *testing.T) {
 	testMovingFunctionError(t, "movingAverage(foo.bar.baz, 0)")
 }
 
+func TestMovingSumSuccess(t *testing.T) {
+	values := []float64{12.0, 19.0, -10.0, math.NaN(), 10.0}
+	bootstrap := []float64{3.0, 4.0, 5.0}
+	expected := []float64{12.0, 21.0, 36.0, 21.0, 9.0} // (3+4+5), (4+5+12), (5+12+19), (12+19-10), (19-10+Nan)
+
+	testMovingAverage(t, "movingSum(foo.bar.baz, '30s')", "movingAverage(foo.bar.baz,\"30s\")", values, bootstrap, expected)
+	testMovingAverage(t, "movingSum(foo.bar.baz, '30s')", "movingAverage(foo.bar.baz,3)", nil, nil, nil)
+
+	bootstrapEntireSeries := []float64{3.0, 4.0, 5.0, 12.0, 19.0, -10.0, math.NaN(), 10.0}
+	testMovingAverage(t, "movingSum(foo.bar.baz, '30s')", "movingAverage(foo.bar.baz,\"30s\")", values, bootstrapEntireSeries, expected)
+}
+
+func TestMovingSumError(t *testing.T) {
+	testMovingAverageError(t, "movingSum(foo.bar.baz, '-30s')")
+	testMovingAverageError(t, "movingSum(foo.bar.baz, 0)")
+}
+
 func TestIsNonNull(t *testing.T) {
 	ctx := common.NewTestContext()
 	defer ctx.Close()
@@ -2547,7 +2564,7 @@ func TestMovingMedianInvalidLimits(t *testing.T) {
 func TestMovingMismatchedLimits(t *testing.T) {
 	// NB: this tests the behavior when query limits do not snap exactly to data
 	// points. When limits do not snap exactly, the first point should be omitted.
-	for _, fn := range []string{"movingAverage", "movingMedian"} {
+	for _, fn := range []string{"movingAverage", "movingMedian", "movingSum"} {
 		for i := time.Duration(0); i < time.Minute; i += time.Second {
 			testMovingAverageInvalidLimits(t, fn, i)
 		}
@@ -2961,6 +2978,7 @@ func TestFunctionsRegistered(t *testing.T) {
 		"mostDeviant",
 		"movingAverage",
 		"movingMedian",
+		"movingSum",
 		"multiplySeries",
 		"nonNegativeDerivative",
 		"nPercentile",