enh: add tests for input and output redirect

Author: marco-souza

lua_test.go

@@ -2,9 +2,12 @@ package lua_test
 
 import (
 	"fmt"
+	"io"
+	"os"
 	"testing"
 
 	"github.com/Shopify/go-lua"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestPushFStringPointer(t *testing.T) {
@@ -31,3 +34,57 @@ func TestToBooleanOutOfRange(t *testing.T) {
 		}
 	}
 }
+
+func TestInputOutputErrorRedirect(t *testing.T) {
+	t.Run("test redirect stdout", func(t *testing.T) {
+		// use a variable as stdout
+		reader, writer, err := os.Pipe()
+		assert.Nil(t, err)
+
+		// setup runtime state
+		l := lua.NewState()
+		l.SetStdout(writer)
+		lua.OpenLibraries(l)
+
+		// run lua code
+		err = lua.DoString(l, "print(1 + 1)")
+		assert.Nil(t, err)
+
+		writer.Close()
+		output, err := io.ReadAll(reader)
+		assert.Nil(t, err)
+
+		assert.Equal(t, "2\n", string(output))
+	})
+
+	t.Run("test std redirect", func(t *testing.T) {
+		// create a pipe to stdin and add some lua code it it
+		inputReader, inputWriter, err := os.Pipe()
+		assert.Nil(t, err)
+
+		outputReader, outputWriter, err := os.Pipe()
+		assert.Nil(t, err)
+
+		// setup runtime state
+		l := lua.NewState()
+		l.SetStdin(inputReader)
+		l.SetStdout(outputWriter)
+		lua.OpenLibraries(l)
+
+		// write to the file input
+		_, err = inputWriter.Write([]byte("print(1 + 1)"))
+		assert.Nil(t, err)
+		assert.Nil(t, inputWriter.Close())
+
+		// run lua code
+		err = lua.DoFile(l, "")
+		assert.Nil(t, err)
+		assert.Nil(t, outputWriter.Close())
+
+		output, err := io.ReadAll(outputReader)
+		assert.Nil(t, err)
+
+		assert.Equal(t, "2\n", string(output))
+	})
+
+}