Merge pull request #2 from deis/utils

feat(utils): adding selected utils

Author: arschles

utils/utils.go

@@ -0,0 +1,65 @@
+package utils
+
+// this is code taken from the v2 branch of github.com/deis/deis/tests/utils
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+)
+
+// RunCommandWithStdoutStderr execs a command and returns its output.
+func RunCommandWithStdoutStderr(cmd *exec.Cmd) (bytes.Buffer, bytes.Buffer, error) {
+	var stdout, stderr bytes.Buffer
+	stderrPipe, err := cmd.StderrPipe()
+	stdoutPipe, err := cmd.StdoutPipe()
+
+	cmd.Env = os.Environ()
+	if err != nil {
+		fmt.Println("error at io pipes")
+	}
+
+	err = cmd.Start()
+	if err != nil {
+		fmt.Println("error at command start")
+	}
+
+	go func() {
+		streamOutput(stdoutPipe, &stdout, os.Stdout)
+	}()
+	go func() {
+		streamOutput(stderrPipe, &stderr, os.Stderr)
+	}()
+	err = cmd.Wait()
+	if err != nil {
+		fmt.Println("error at command wait")
+	}
+	return stdout, stderr, err
+}
+
+// streamOutput from a source to a destination buffer while also printing
+func streamOutput(src io.Reader, dst *bytes.Buffer, out io.Writer) error {
+	mw := io.MultiWriter(dst, out)
+	s := bufio.NewReader(src)
+	for {
+		var line []byte
+		line, err := s.ReadSlice('\n')
+		if err == io.EOF && len(line) == 0 {
+			break // done
+		}
+		if err == io.EOF {
+			return fmt.Errorf("Improper termination: %v", line)
+		}
+		if err != nil {
+			return err
+		}
+
+		// append to the buffer and out at once
+		mw.Write(line)
+	}
+
+	return nil
+}

utils/utils_test.go

@@ -0,0 +1,41 @@
+package utils
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func TestStreamOuptutSuccess(t *testing.T) {
+	str := "abc\ndef\n"
+	src := strings.NewReader(str)
+	dest := bytes.NewBuffer(nil)
+	out := bytes.NewBuffer(nil)
+
+	err := streamOutput(src, dest, out)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	destStr := string(dest.Bytes())
+	if destStr != str {
+		t.Fatalf("dest was [%s], expected [%s]", destStr, str)
+	}
+
+	outStr := string(out.Bytes())
+	if outStr != str {
+		t.Fatalf("out was [%s], expected [%s]", outStr, str)
+	}
+}
+
+func TestStreamOutputErr(t *testing.T) {
+	// no ending newline
+	str := "abc\ndef"
+	src := strings.NewReader(str)
+	dest := bytes.NewBuffer(nil)
+	out := bytes.NewBuffer(nil)
+	err := streamOutput(src, dest, out)
+	if err == nil {
+		t.Fatal("expected an error for a string that doesn't end with a newline")
+	}
+}