testing script

Author: Jessica Xie

fixtures/io.txt

@@ -0,0 +1,5 @@
+A banana contains 75% water.
+The most consumed fruit in America is the banana
+Bananas are a good source of vitamin C, potassium and fiber.
+Fresh apples float because they contain 25% air.
+Bananas contain no fat, cholesterol or sodium.

fixtures/number.txt

@@ -0,0 +1 @@
+12345

fixtures/read_all.lua

@@ -0,0 +1,3 @@
+file = io.open("fixtures/io.txt", "r")
+print(file:read("*a"))
+file:close()

fixtures/read_bytes.lua

@@ -0,0 +1,3 @@
+file = io.open("fixtures/io.txt", "r")
+print(file:read(20))
+file:close()

fixtures/read_lines.lua

@@ -0,0 +1,4 @@
+file = io.open("fixtures/io.txt", "r")
+print(file:read("*l"))
+print(file:read("*l"))
+file:close()

fixtures/read_number.lua

@@ -0,0 +1,3 @@
+file = io.open("fixtures/number.txt", "r")
+print(file:read("*n"))
+file:close()

io.go

@@ -125,18 +125,24 @@ func readAll(l *State, f *os.File) error {
 }
 
 func readLineHelper(l *State, f *os.File) error {
-	// TODO: you can only read one line. After one line, the file is closed.
+	originalFileOffset, err := f.Seek(0, 1)
+	if err != nil {
+		return err
+	}
+
 	reader := bufio.NewReader(f)
 	bytes, err := reader.ReadBytes('\n')
 	if err == nil {
 		l.PushString(string(bytes))
+		length := int64(len(bytes))
+		f.Seek(originalFileOffset+length, 0) // bufio loads the entire file. This is a lazy hack to get around the problem.
 	}
 	return err
 }
 
 func readBytes(l *State, f *os.File, i int) error {
 	buf := make([]byte, i)
-	_, err := io.ReadFull(f, buf)
+	_, err := f.Read(buf)
 	if err == nil {
 		l.PushString(string(buf))
 	}

io_test.go

@@ -0,0 +1,85 @@
+package lua
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+)
+
+// TODO: add missing tests
+
+func TestReadAll(t *testing.T) {
+	l := NewState()
+	OpenLibraries(l)
+	output := captureOutput(func() {
+		DoFile(l, "fixtures/read_all.lua")
+	})
+
+	expected := `A banana contains 75% water.
+The most consumed fruit in America is the banana
+Bananas are a good source of vitamin C, potassium and fiber.
+Fresh apples float because they contain 25% air.
+Bananas contain no fat, cholesterol or sodium.`
+
+	if strings.Trim(output, "\n") != expected {
+		t.Errorf("Expecting:\n%s\nbut received:\n%s\n", expected, output)
+	}
+}
+
+func TestReadLines(t *testing.T) {
+	l := NewState()
+	OpenLibraries(l)
+	output := captureOutput(func() {
+		DoFile(l, "fixtures/read_lines.lua")
+	})
+
+	expected := `A banana contains 75% water.
+
+The most consumed fruit in America is the banana`
+
+	if strings.Trim(output, "\n") != expected {
+		t.Errorf("Expecting:\n%s\nbut received:\n%s\n", expected, output)
+	}
+}
+
+func TestReadNumber(t *testing.T) {
+	l := NewState()
+	OpenLibraries(l)
+	output := captureOutput(func() {
+		DoFile(l, "fixtures/read_number.lua")
+	})
+
+	expected := "12345"
+	if strings.Trim(output, "\n") != expected {
+		t.Errorf("Expecting:\n%s\nbut received:\n%s\n", expected, output)
+	}
+}
+
+func TestReadBytes(t *testing.T) {
+	l := NewState()
+	OpenLibraries(l)
+	output := captureOutput(func() {
+		DoFile(l, "fixtures/read_bytes.lua")
+	})
+
+	expected := "A banana contains 75"
+	if strings.Trim(output, "\n") != expected {
+		t.Errorf("Expecting:\n%s\nbut received:\n%s\n", expected, output)
+	}
+}
+
+func captureOutput(f func()) string {
+	rescueStdout := os.Stdout
+	r, w, _ := os.Pipe()
+	os.Stdout = w
+
+	f()
+
+	w.Close()
+	out, _ := ioutil.ReadAll(r)
+	fmt.Println(string(out))
+	os.Stdout = rescueStdout
+	return string(out)
+}