feat: API improvements to open and close files (#4)

* io methods: read, save, open, write

* methods ordering

* some more tests

io.go

@@ -4,35 +4,62 @@ import (
 	"bytes"
 	"encoding/xml"
 	"fmt"
+	"io"
 	"os"
 )
 
-// Write writes the ComicInfo spec to the specified path.
-func Write(ci ComicInfo, path string) error {
+// Read reads the ComicInfo spec from the specified reader
+func Read(r io.Reader) (*ComicInfo, error) {
+	var ci ComicInfo
+	err := xml.NewDecoder(r).Decode(&ci)
+	if err != nil {
+		return nil, fmt.Errorf("error unmarshalling ComicInfo: %w", err)
+	}
+
+	return &ci, nil
+}
+
+// Write writes the ComicInfo spec to the specified writter
+func Write(ci *ComicInfo, w io.Writer) error {
 	contents, err := xml.Marshal(ci)
 	if err != nil {
 		return fmt.Errorf("error marshalling ComicInfo: %w", err)
 	}
 
-	err = os.WriteFile(path, bytes.Join([][]byte{xmlHeader, contents}, []byte("")), 0644)
+	_, err = w.Write(bytes.Join([][]byte{xmlHeader, contents}, []byte("")))
 	if err != nil {
 		return fmt.Errorf("error writing ComicInfo to file: %w", err)
 	}
 	return nil
 }
 
 // Read reads the ComicInfo spec from the specified path.
-func Open(path string) (ComicInfo, error) {
+func Open(path string) (*ComicInfo, error) {
 	f, err := os.ReadFile(path)
 	if err != nil {
-		return ComicInfo{}, fmt.Errorf("error reading file: %w", err)
+		return nil, fmt.Errorf("error reading file: %w", err)
 	}
 
 	var ci ComicInfo
 	err = xml.Unmarshal(f, &ci)
 	if err != nil {
-		return ComicInfo{}, fmt.Errorf("error unmarshalling ComicInfo: %w", err)
+		return nil, fmt.Errorf("error unmarshalling ComicInfo: %w", err)
+	}
+
+	return &ci, nil
+}
+
+// Save writes the ComicInfo spec to the specified path.
+func Save(ci *ComicInfo, path string) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return fmt.Errorf("error creating file: %w", err)
+	}
+
+	err = Write(ci, f)
+	if err != nil {
+		return fmt.Errorf("error writing ComicInfo to file: %w", err)
 	}
 
-	return ci, nil
+	return nil
 }

io_test.go

@@ -1,29 +1,60 @@
 package comicinfo
 
 import (
+	"bytes"
 	"path/filepath"
 	"testing"
 
 	"github.com/stretchr/testify/require"
 )
 
-func TestWriteRead(t *testing.T) {
+func TestSaveOpen(t *testing.T) {
 	tmpDir := t.TempDir()
-	ci := ComicInfo{
+	ci := &ComicInfo{
 		Title: "Test",
 	}
 
-	path := filepath.Join(tmpDir, "test.xml")
+	path := filepath.Join(tmpDir, "comicinfo.xml")
 
-	err := Write(ci, path)
+	err := Save(ci, path)
 	if err != nil {
-		t.Errorf("error writing ComicInfo: %v", err)
+		t.Fatalf("error writing ComicInfo: %v", err)
 	}
 
 	ci2, err := Open(path)
 	if err != nil {
-		t.Errorf("error reading ComicInfo: %v", err)
+		t.Fatalf("error reading ComicInfo: %v", err)
 	}
 
 	require.Equal(t, ci, ci2)
 }
+
+func TestWriteOpen(t *testing.T) {
+	ci := &ComicInfo{
+		Title: "Test",
+	}
+
+	var buf bytes.Buffer
+
+	err := Write(ci, &buf)
+	if err != nil {
+		t.Fatalf("error writing ComicInfo: %v", err)
+	}
+
+	ci2, err := Read(&buf)
+	if err != nil {
+		t.Fatalf("error reading ComicInfo: %v", err)
+	}
+
+	require.Equal(t, ci, ci2)
+}
+
+func TestReadError(t *testing.T) {
+	_, err := Read(bytes.NewReader([]byte("")))
+	require.Error(t, err)
+}
+
+func TestOpenError(t *testing.T) {
+	_, err := Open("nonexistent.xml")
+	require.Error(t, err)
+}

schema.go

@@ -57,10 +57,10 @@ func (ci *ComicInfo) SetXMLAttributes() {
 }
 
 // New provides a new ComicInfo struct with the XML attributes set
-func NewComicInfo() ComicInfo {
+func NewComicInfo() *ComicInfo {
 	ci := ComicInfo{}
 	ci.SetXMLAttributes()
-	return ci
+	return &ci
 }
 
 // YesNo defines the YesNo type

schema_test.go

@@ -77,24 +77,26 @@ func TestFullSchema(t *testing.T) {
 	ci.AgeRating = AgeRatingEveryone
 	ci.MainCharacterOrTeam = "Test"
 	ci.Review = "Test"
-	ci.Pages.Pages = append(ci.Pages.Pages, ComicPageInfo{
-		Image:       1,
-		Type:        ComicPageTypeEditorial,
-		DoublePage:  false,
-		ImageSize:   999,
-		Key:         "?",
-		Bookmark:    "yes",
-		ImageWidth:  20,
-		ImageHeight: 21,
-	})
 	ci.CommunityRating = 5.0
 	ci.MainCharacterOrTeam = "Test"
 	ci.Review = "Test"
 
+	page := NewComicPageInfo()
+	page.Image = 1
+	page.Type = ComicPageTypeEditorial
+	page.DoublePage = false
+	page.ImageSize = 999
+	page.Key = "?"
+	page.Bookmark = "yes"
+	page.ImageWidth = 20
+	page.ImageHeight = 21
+
+	ci.Pages.Pages = append(ci.Pages.Pages, page)
+
 	// Write the ComicInfo struct to a temporary file
 	ciPath := filepath.Join(tmpDir, "comicinfo.xml")
 
-	err = Write(ci, ciPath)
+	err = Save(ci, ciPath)
 	if err != nil {
 		t.Errorf("error writing ComicInfo: %v", err)
 	}