Extend API, more error checking

Makefile

@@ -1,6 +1,6 @@
 BINARY =
 TARGET =
-LINT_PACKAGES = io*.go
+LINT_PACKAGES = *.go
 COVERPROFILES = *.coverprofile
 COVERPROFILE = goverprofile
 CWD = $(shell pwd)

io.go → wrap.go

@@ -7,30 +7,44 @@ import (
 
 // WrapStdout will collect everything sent to the standard output
 // while `functor` is executed in return it in a string
-func WrapStdout(functor func()) []byte {
+func WrapStdout(functor func()) ([]byte, error) {
 	backup := os.Stdout
-	r, w, _ := os.Pipe()
+	r, w, err := os.Pipe()
+	if err != nil {
+		return nil, err
+	}
 	os.Stdout = w
 	defer func() {
 		os.Stdout = backup
 	}()
 	functor()
 	w.Close()
-	content, _ := ioutil.ReadAll(r)
-	return content
+	content, err := ioutil.ReadAll(r)
+	r.Close()
+	if err != nil {
+		return nil, err
+	}
+	return content, nil
 }
 
 // WrapStderr will collect everything sent to the standard error output
 // while `functor` is executed in return it in a string
-func WrapStderr(functor func()) []byte {
+func WrapStderr(functor func()) ([]byte, error) {
 	backup := os.Stderr
-	r, w, _ := os.Pipe()
+	r, w, err := os.Pipe()
+	if err != nil {
+		return nil, err
+	}
 	os.Stderr = w
 	defer func() {
 		os.Stderr = backup
 	}()
 	functor()
 	w.Close()
-	content, _ := ioutil.ReadAll(r)
-	return content
+	content, err := ioutil.ReadAll(r)
+	r.Close()
+	if err != nil {
+		return nil, err
+	}
+	return content, nil
 }

io_test.go → wrap_test.go

@@ -9,15 +9,19 @@ import (
 )
 
 func TestWrapStdout_Works(t *testing.T) {
-	content := WrapStdout(func() {
+	content, err := WrapStdout(func() {
 		fmt.Printf("123\n")
 	})
-	assert.Equal(t, "123\n", string(content))
+	if assert.NoError(t, err) {
+		assert.Equal(t, "123\n", string(content))
+	}
 }
 
 func TestWrapStderr_Works(t *testing.T) {
-	content := WrapStderr(func() {
+	content, err := WrapStderr(func() {
 		fmt.Fprintf(os.Stderr, "456\n")
 	})
-	assert.Equal(t, "456\n", string(content))
+	if assert.NoError(t, err) {
+		assert.Equal(t, "456\n", string(content))
+	}
 }

writer.go

@@ -0,0 +1,25 @@
+package iowrap
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+)
+
+// Writer returns a writer that will collect all output and which can then be
+// accessed by calling the second return (which will also close the writer)
+func Writer() (io.Writer, func() ([]byte, error), error) {
+	r, w, err := os.Pipe()
+	if err != nil {
+		return nil, nil, err
+	}
+	return w, func() ([]byte, error) {
+		w.Close()
+		content, err := ioutil.ReadAll(r)
+		r.Close()
+		if err != nil {
+			return nil, err
+		}
+		return content, nil
+	}, nil
+}

writer_test.go

@@ -0,0 +1,22 @@
+package iowrap
+
+import (
+	"log"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestWriter_Works(t *testing.T) {
+	w, collect, err := Writer()
+	if !assert.NoError(t, err) {
+		return
+	}
+
+	log.SetOutput(w)
+	log.Printf("hello123")
+	content, err := collect()
+	if assert.NoError(t, err) {
+		assert.Regexp(t, " hello123\n$", string(content))
+	}
+}