no need to return string when using io.Writer anyway

lib/printer.go

@@ -29,7 +29,7 @@ import (
 	"strings"
 )
 
-func printData(w io.Writer, data *Tabdata) string {
+func printData(w io.Writer, data *Tabdata) {
 	// some output preparations:
 
 	// add numbers to headers and remove this we're not interested in
@@ -43,31 +43,30 @@ func printData(w io.Writer, data *Tabdata) string {
 
 	switch OutputMode {
 	case "extended":
-		return printExtendedData(w, data)
+		printExtendedData(w, data)
 	case "ascii":
-		return printAsciiData(w, data)
+		printAsciiData(w, data)
 	case "orgtbl":
-		return printOrgmodeData(w, data)
+		printOrgmodeData(w, data)
 	case "markdown":
-		return printMarkdownData(w, data)
+		printMarkdownData(w, data)
 	case "shell":
-		return printShellData(w, data)
+		printShellData(w, data)
 	case "yaml":
-		return printYamlData(w, data)
+		printYamlData(w, data)
 	default:
-		return printAsciiData(w, data)
+		printAsciiData(w, data)
 	}
 }
 
-func output(w io.Writer, str string) string {
+func output(w io.Writer, str string) {
 	fmt.Fprint(w, str)
-	return str
 }
 
 /*
    Emacs org-mode compatible table (also orgtbl-mode)
 */
-func printOrgmodeData(w io.Writer, data *Tabdata) string {
+func printOrgmodeData(w io.Writer, data *Tabdata) {
 	tableString := &strings.Builder{}
 	table := tablewriter.NewWriter(tableString)
 
@@ -93,7 +92,7 @@ func printOrgmodeData(w io.Writer, data *Tabdata) string {
 	leftR := regexp.MustCompile("(?m)^\\+")
 	rightR := regexp.MustCompile("\\+(?m)$")
 
-	return output(w, color.Sprint(
+	output(w, color.Sprint(
 		colorizeData(
 			rightR.ReplaceAllString(
 				leftR.ReplaceAllString(tableString.String(), "|"), "|"))))
@@ -102,7 +101,7 @@ func printOrgmodeData(w io.Writer, data *Tabdata) string {
 /*
    Markdown table
 */
-func printMarkdownData(w io.Writer, data *Tabdata) string {
+func printMarkdownData(w io.Writer, data *Tabdata) {
 	tableString := &strings.Builder{}
 	table := tablewriter.NewWriter(tableString)
 
@@ -116,13 +115,13 @@ func printMarkdownData(w io.Writer, data *Tabdata) string {
 	table.SetCenterSeparator("|")
 
 	table.Render()
-	return output(w, color.Sprint(colorizeData(tableString.String())))
+	output(w, color.Sprint(colorizeData(tableString.String())))
 }
 
 /*
    Simple ASCII table without any borders etc, just like the input we expect
 */
-func printAsciiData(w io.Writer, data *Tabdata) string {
+func printAsciiData(w io.Writer, data *Tabdata) {
 	tableString := &strings.Builder{}
 	table := tablewriter.NewWriter(tableString)
 
@@ -146,13 +145,13 @@ func printAsciiData(w io.Writer, data *Tabdata) string {
 	table.SetNoWhiteSpace(true)
 
 	table.Render()
-	return output(w, color.Sprint(colorizeData(tableString.String())))
+	output(w, color.Sprint(colorizeData(tableString.String())))
 }
 
 /*
    We simulate the \x command of psql (the PostgreSQL client)
 */
-func printExtendedData(w io.Writer, data *Tabdata) string {
+func printExtendedData(w io.Writer, data *Tabdata) {
 	// needed for data output
 	format := fmt.Sprintf("%%%ds: %%s\n", data.maxwidthHeader)
 	out := ""
@@ -166,13 +165,13 @@ func printExtendedData(w io.Writer, data *Tabdata) string {
 		}
 	}
 
-	return output(w, out)
+	output(w, out)
 }
 
 /*
    Shell output, ready to be eval'd. Just like FreeBSD stat(1)
 */
-func printShellData(w io.Writer, data *Tabdata) string {
+func printShellData(w io.Writer, data *Tabdata) {
 	out := ""
 	if len(data.entries) > 0 {
 		for _, entry := range data.entries {
@@ -184,10 +183,10 @@ func printShellData(w io.Writer, data *Tabdata) string {
 			out += fmt.Sprint(strings.Join(shentries, " ")) + "\n"
 		}
 	}
-	return output(w, out)
+	output(w, out)
 }
 
-func printYamlData(w io.Writer, data *Tabdata) string {
+func printYamlData(w io.Writer, data *Tabdata) {
 	type D struct {
 		Entries []map[string]interface{} `yaml:"entries"`
 	}
@@ -220,5 +219,5 @@ func printYamlData(w io.Writer, data *Tabdata) string {
 		log.Fatal(err)
 	}
 
-	return output(w, string(yamlstr))
+	output(w, string(yamlstr))
 }

lib/printer_test.go

@@ -279,11 +279,15 @@ func TestPrinter(t *testing.T) {
 			}
 
 			testdata := mockdata
-			output := strings.TrimSpace(printData(&w, &testdata))
 			exp := strings.TrimSpace(tt.expect)
-			if output != exp {
+
+			printData(&w, &testdata)
+
+			got := strings.TrimSpace(w.String())
+
+			if got != exp {
 				t.Errorf("not rendered correctly:\n+++ got:\n%s\n+++ want:\n%s",
-					output, exp)
+					got, exp)
 			}
 		})
 	}