Add multiplexed writer test

Author: SimonBaeumer

command_linux_test.go

@@ -131,3 +131,10 @@ func TestWithStandardStreams(t *testing.T) {
 	assertEqualWithLineBreak(t, "stderr\nstdout", out)
 	assert.Nil(t, err)
 }
+
+func TestWithEnvironmentVariables(t *testing.T) {
+	c := NewCommand("echo $env", WithEnvironmentVariables(map[string]string{"env": "value"}))
+	c.Execute()
+
+	assertEqualWithLineBreak(t, "value", c.Stdout())
+}

command_test.go

@@ -126,10 +126,3 @@ func TestCommand_SetOptions(t *testing.T) {
 	assert.Equal(t, time.Duration(1000000000), c.Timeout)
 	assertEqualWithLineBreak(t, "test", writer.String())
 }
-
-func TestWithEnvironmentVariables(t *testing.T) {
-	c := NewCommand("echo $env", WithEnvironmentVariables(map[string]string{"env": "value"}))
-	c.Execute()
-
-	assertEqualWithLineBreak(t, "value", c.Stdout())
-}

multiplexed_writer.go

@@ -1,6 +1,7 @@
 package cmd
 
 import (
+	"fmt"
 	"io"
 )
 
@@ -20,7 +21,7 @@ func (w MultiplexedWriter) Write(p []byte) (n int, err error) {
 	for _, o := range w.Outputs {
 		n, err = o.Write(p)
 		if err != nil {
-			return 0, nil
+			return 0, fmt.Errorf("Error in writer: %s", err.Error())
 		}
 	}
 

multiplexed_writer_test.go

@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"bytes"
+	"fmt"
 	"github.com/stretchr/testify/assert"
 	"os"
 	"testing"
@@ -38,3 +39,19 @@ func TestMultiplexedWriter_SingleWirter(t *testing.T) {
 	assert.Equal(t, 7, n)
 	assert.Equal(t, "another", writer01.String())
 }
+
+func TestMultiplexedWriter_Fail(t *testing.T) {
+	writer := NewMultiplexedWriter(InvalidWriter{})
+
+	n, err := writer.Write([]byte(`another`))
+
+	assert.Equal(t, 0, n)
+	assert.Equal(t, "Error in writer: failed", err.Error())
+}
+
+type InvalidWriter struct {
+}
+
+func (w InvalidWriter) Write(p []byte) (n int, err error) {
+	return 0, fmt.Errorf("failed")
+}