added more UNIT test cases for covering all parts of the code

added debug statement for debugging OpenTSDB communication

Closes #182

outputs/opentsdb/opentsdb_test.go

@@ -3,7 +3,9 @@ package opentsdb
 import (
 	"reflect"
 	"testing"
+	"time"
 
+	"github.com/influxdb/influxdb/client"
 	"github.com/influxdb/telegraf/testutil"
 	"github.com/stretchr/testify/require"
 )
@@ -60,4 +62,34 @@ func TestWrite(t *testing.T) {
 	// Verify that we can successfully write data to OpenTSDB
 	err = o.Write(testutil.MockBatchPoints())
 	require.NoError(t, err)
+
+	// Verify postive and negative test cases of writing data
+	var bp client.BatchPoints
+	bp.Time = time.Now()
+	bp.Tags = map[string]string{"testkey": "testvalue"}
+	bp.Points = []client.Point{
+		{
+			Measurement: "justametric.float",
+			Fields:      map[string]interface{}{"value": float64(1.0)},
+		},
+		{
+			Measurement: "justametric.int",
+			Fields:      map[string]interface{}{"value": int64(123456789)},
+		},
+		{
+			Measurement: "justametric.uint",
+			Fields:      map[string]interface{}{"value": uint64(123456789012345)},
+		},
+		{
+			Measurement: "justametric.string",
+			Fields:      map[string]interface{}{"value": "Lorem Ipsum"},
+		},
+		{
+			Measurement: "justametric.anotherfloat",
+			Fields:      map[string]interface{}{"value": float64(42.0)},
+		},
+	}
+	err = o.Write(bp)
+	require.NoError(t, err)
+
 }