test-results: Add merge and trim methods

go/src/infra/appengine/test-results/model/full_result.go

Index: go/src/infra/appengine/test-results/model/full_result.go
diff --git a/go/src/infra/appengine/test-results/model/full_result.go b/go/src/infra/appengine/test-results/model/full_result.go
index 0caebf7b5508369acd2c754f4691a730f201d27b..d99463cf5bddd5ef1d64b4fc42b2dd2a848d1f07 100644
--- a/go/src/infra/appengine/test-results/model/full_result.go
+++ b/go/src/infra/appengine/test-results/model/full_result.go
@@ -3,6 +3,7 @@ package model
 import (
 	"encoding/json"
 	"errors"
+	"math"
 	"strings"
 )
 
@@ -283,13 +284,20 @@ func (l *FullTestLeaf) AggregateTestLeaf() (AggregateTestLeaf, error) {
 
 	var time float64
 	if l.Runtime != nil {
-		time = *l.Runtime
+		time = float64(round(*l.Runtime))
 	}
 	ret.Runtimes = []RuntimeSummary{{1, time}}
 
 	return ret, nil
 }
 
+func round(f float64) int {
+	if math.Abs(f) < 0.5 {
+		return 0
+	}
+	return int(f + math.Copysign(0.5, f))
+}
+
 // MarshalJSON marshals l into JSON.
 func (l *FullTestLeaf) MarshalJSON() ([]byte, error) {
 	aux := testResultAux{fullTestLeafAlias: (*fullTestLeafAlias)(l)}