Implement Msg.String()

Change-Id: I36f7d44d2dc66fa7e51f9f05d13f3767c800fd34

Author: tfogo

x/network/wiremessage/msg.go

@@ -8,6 +8,7 @@ package wiremessage
 
 import (
 	"errors"
+	"fmt"
 
 	"go.mongodb.org/mongo-driver/bson"
 	"go.mongodb.org/mongo-driver/x/bsonx"
@@ -63,7 +64,10 @@ func (m Msg) AppendWireMessage(b []byte) ([]byte, error) {
 
 // String implements the fmt.Stringer interface.
 func (m Msg) String() string {
-	panic("not implemented")
+	return fmt.Sprintf(
+		`OP_MSG{MsgHeader: %v, FlagBits: %d, Sections: %v, Checksum: %d}`,
+		m.MsgHeader, m.FlagBits, m.Sections, m.Checksum,
+	)
 }
 
 // Len implements the WireMessage interface.

x/network/wiremessage/msg_test.go

@@ -106,4 +106,28 @@ func TestMsg(t *testing.T) {
 			})
 		}
 	})
+
+	t.Run("WireMessageToString", func(t *testing.T) {
+		msgHeader := Header{
+			MessageLength: 33,
+			RequestID:     0,
+			ResponseTo:    0,
+			OpCode:        2013,
+		}
+
+		msg := Msg{
+			MsgHeader: msgHeader,
+			FlagBits:  0,
+			Sections:  oneSection(t),
+		}
+
+		var msgString string
+
+		msgString = "OP_MSG{MsgHeader: Header{MessageLength: 33, RequestID: 0, ResponseTo: 0, OpCode: OP_MSG}, " +
+			"FlagBits: 0, Sections: [{0 {\"x\": {\"$numberInt\":\"5\"}}}], Checksum: 0}"
+
+		if msg.String() != msgString {
+			t.Errorf("Did not get expected string. got:\n%s\n\nexpected:\n%s", msg.String(), msgString)
+		}
+	})
 }