kubectl: move events sorting interface to the api for general use

pkg/kubectl/describe_test.go

@@ -170,6 +170,30 @@ func TestPodDescribeResultsSorted(t *testing.T) {
 	VerifyDatesInOrder(out, "\n" /* rowDelimiter */, "\t" /* columnDelimiter */, t)
 }
 
+// VerifyDatesInOrder checks the start of each line for a RFC1123Z date
+// and posts error if all subsequent dates are not equal or increasing
+func VerifyDatesInOrder(
+	resultToTest, rowDelimiter, columnDelimiter string, t *testing.T) {
+	lines := strings.Split(resultToTest, rowDelimiter)
+	var previousTime time.Time
+	for _, str := range lines {
+		columns := strings.Split(str, columnDelimiter)
+		if len(columns) > 0 {
+			currentTime, err := time.Parse(time.RFC1123Z, columns[0])
+			if err == nil {
+				if previousTime.After(currentTime) {
+					t.Errorf(
+						"Output is not sorted by time. %s should be listed after %s. Complete output: %s",
+						previousTime.Format(time.RFC1123Z),
+						currentTime.Format(time.RFC1123Z),
+						resultToTest)
+				}
+				previousTime = currentTime
+			}
+		}
+	}
+}
+
 func TestDescribeContainers(t *testing.T) {
 	testCases := []struct {
 		container        api.Container