Use buffer as a var instead of NewBuffer(nil). (#312)

internal/report/report_test.go

 			want: path + "source.dot",
 		},
 	} {
-		b := bytes.NewBuffer(nil)
-		if err := Generate(b, tc.rpt, &binutils.Binutils{}); err != nil {
+		var b bytes.Buffer
+		if err := Generate(&b, tc.rpt, &binutils.Binutils{}); err != nil {
 			t.Fatalf("%s: %v", tc.want, err)
 		}
 

internal/report/source_test.go

 		SampleValue:  func(v []int64) int64 { return v[1] },
 		SampleUnit:   cpu.SampleType[1].Unit,
 	})
-	buf := bytes.NewBuffer(nil)
-	if err := Generate(buf, rpt, &binutils.Binutils{}); err != nil {
+	var buf bytes.Buffer
+	if err := Generate(&buf, rpt, &binutils.Binutils{}); err != nil {
 		t.Fatalf("could not generate weblist: %v", err)
 	}
 	output := buf.String()

profile/profile_test.go

 		}
 
 		// Reencode and decode.
-		bw := bytes.NewBuffer(nil)
-		if err := p.Write(bw); err != nil {
+		var bw bytes.Buffer
+		if err := p.Write(&bw); err != nil {
 			t.Fatalf("%s: %v", source, err)
 		}
-		if p, err = Parse(bw); err != nil {
+		if p, err = Parse(&bw); err != nil {
 			t.Fatalf("%s: %v", source, err)
 		}
 		js2 := p.String()
 func TestParseConcatentated(t *testing.T) {
 	prof := testProfile1.Copy()
 	// Write the profile twice to buffer to create concatented profile.
-	buf := bytes.NewBuffer(nil)
-	prof.Write(buf)
-	prof.Write(buf)
-	_, err := Parse(buf)
+	var buf bytes.Buffer
+	prof.Write(&buf)
+	prof.Write(&buf)
+	_, err := Parse(&buf)
 	if err == nil {
 		t.Fatalf("got nil, want error")
 	}

profile/proto_test.go

 
 func TestMarshalUnmarshal(t *testing.T) {
 	// Write the profile, parse it, and ensure they're equal.
-	buf := bytes.NewBuffer(nil)
-	all.Write(buf)
-	all2, err := Parse(buf)
+	var buf bytes.Buffer
+	all.Write(&buf)
+	all2, err := Parse(&buf)
 	if err != nil {
 		t.Fatal(err)
 	}