add RunCommandAndGetStdOutErr

modules/shell/command.go

@@ -84,6 +84,27 @@ func RunCommandAndGetStdOutE(t testing.TestingT, command Command) (string, error
 	return output.Stdout(), nil
 }
 
+// RunCommandAndGetStdOutErr runs a shell command and returns solely its stdout and stderr as a string. The stdout and
+// stderr of that command will also be logged with Command.Log to make debugging easier. If there are any errors, fail
+// the test.
+func RunCommandAndGetStdOutErr(t testing.TestingT, command Command) (stdout string, stderr string) {
+	stdout, stderr, err := RunCommandAndGetStdOutErrE(t, command)
+	require.NoError(t, err)
+	return stdout, stderr
+}
+
+// RunCommandAndGetStdOutErrE runs a shell command and returns solely its stdout and stderr as a string. The stdout
+// and stderr of that command will also be printed to the stdout and stderr of this Go program to make debugging easier.
+// Any returned error will be of type ErrWithCmdOutput, containing the output streams and the underlying error.
+func RunCommandAndGetStdOutErrE(t testing.TestingT, command Command) (stdout string, stderr string, err error) {
+	output, err := runCommand(t, command)
+	if err != nil {
+		return output.Stdout(), output.Stderr(), &ErrWithCmdOutput{err, output}
+	}
+
+	return output.Stdout(), output.Stderr(), nil
+}
+
 type ErrWithCmdOutput struct {
 	Underlying error
 	Output     *output

modules/shell/command_test.go

@@ -8,6 +8,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/gruntwork-io/terratest/modules/logger"
 	"github.com/gruntwork-io/terratest/modules/random"
@@ -183,3 +184,29 @@ func TestCommandOutputType(t *testing.T) {
 		assert.Len(t, o.Output.Combined(), len(stdout)+len(stderr)+1) // +1 for newline
 	}
 }
+
+func TestCommandWithStdoutAndStdErr(t *testing.T) {
+	t.Parallel()
+
+	stdout := "hello world"
+	stderr := "this command has failed"
+	command := Command{
+		Command: "sh",
+		Args:    []string{"-c", `echo "` + stdout + `" && echo "` + stderr + `" >&2`},
+		Logger:  logger.Discard,
+	}
+
+	t.Run("MustNotError", func(t *testing.T) {
+		ostdout, ostderr := RunCommandAndGetStdOutErr(t, command)
+		assert.Equal(t, stdout, ostdout)
+		assert.Equal(t, stderr, ostderr)
+	})
+
+	t.Run("ReturnError", func(t *testing.T) {
+		ostdout, ostderr, err := RunCommandAndGetStdOutErrE(t, command)
+		require.NoError(t, err)
+		assert.Equal(t, stdout, ostdout)
+		assert.Equal(t, stderr, ostderr)
+	})
+
+}