feature/load fonts as byte streams (#411)

* Add AddUTF8FontFromBytes to repository

Allow to provide font files as Byte streams directly instead of
loading from file. This is specially useful when using `go:embed` to
include the asset files in the binary generating the PDFs.

* fixup! Add AddUTF8FontFromBytes to repository

* Use assert.Len instead of Equal

pkg/repository/repository.go

@@ -11,6 +11,7 @@ import (
 // Repository is the abstraction to load custom fonts.
 type Repository interface {
 	AddUTF8Font(family string, style fontstyle.Type, file string) Repository
+	AddUTF8FontFromBytes(family string, style fontstyle.Type, bytes []byte) Repository
 	Load() ([]*entity.CustomFont, error)
 }
 
@@ -46,9 +47,35 @@ func (r *FontRepository) AddUTF8Font(family string, style fontstyle.Type, file s
 	return r
 }
 
+// AddUTF8FontFromBytes adds a custom font to the repository from a byte slice.
+func (r *FontRepository) AddUTF8FontFromBytes(family string, style fontstyle.Type, bytes []byte) Repository {
+	if family == "" {
+		return r
+	}
+
+	if !style.IsValid() {
+		return r
+	}
+
+	if bytes == nil {
+		return r
+	}
+
+	r.customFonts = append(r.customFonts, &entity.CustomFont{
+		Family: family,
+		Style:  style,
+		Bytes:  bytes,
+	})
+
+	return r
+}
+
 // Load loads all custom fonts.
 func (r *FontRepository) Load() ([]*entity.CustomFont, error) {
 	for _, customFont := range r.customFonts {
+		if customFont.File == "" {
+			continue
+		}
 		bytes, err := os.ReadFile(customFont.File)
 		if err != nil {
 			return nil, err

pkg/repository/repository_test.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/johnfercher/maroto/v2/pkg/consts/fontstyle"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestRepository_AddUTF8Font(t *testing.T) {
@@ -22,7 +23,7 @@ func TestRepository_AddUTF8Font(t *testing.T) {
 
 		// Assert
 		assert.Nil(t, err)
-		assert.Equal(t, 0, len(customFonts))
+		assert.Len(t, customFonts, 0)
 	})
 
 	t.Run("when fontstyle style is invalid, should not add value", func(t *testing.T) {
@@ -34,7 +35,7 @@ func TestRepository_AddUTF8Font(t *testing.T) {
 
 		// Assert
 		assert.Nil(t, err)
-		assert.Equal(t, 0, len(customFonts))
+		assert.Len(t, customFonts, 0)
 	})
 
 	t.Run("when fontstyle file is empty, should not add value", func(t *testing.T) {
@@ -46,7 +47,7 @@ func TestRepository_AddUTF8Font(t *testing.T) {
 
 		// Assert
 		assert.Nil(t, err)
-		assert.Equal(t, 0, len(customFonts))
+		assert.Len(t, customFonts, 0)
 	})
 
 	t.Run("when fontstyle is valid, should not value", func(t *testing.T) {
@@ -58,14 +59,70 @@ func TestRepository_AddUTF8Font(t *testing.T) {
 
 		// Assert
 		assert.Nil(t, err)
-		assert.Equal(t, 1, len(customFonts))
+		assert.Len(t, customFonts, 1)
 		assert.Equal(t, "family", customFonts[0].Family)
 		assert.Equal(t, fontstyle.Bold, customFonts[0].Style)
 		assert.NotEmpty(t, customFonts[0].File)
 		assert.NotEmpty(t, customFonts[0].Bytes)
 	})
 }
 
+func TestRepository_AddUTF8FontFromBytes(t *testing.T) {
+	t.Run("when fontstyle family is empty, should not add value", func(t *testing.T) {
+		// Arrange
+		sut := repository.New()
+
+		// Act
+		customFonts, err := sut.AddUTF8FontFromBytes("", fontstyle.Bold, []byte(``)).Load()
+
+		// Assert
+		assert.Nil(t, err)
+		assert.Len(t, customFonts, 0)
+	})
+
+	t.Run("when fontstyle style is invalid, should not add value", func(t *testing.T) {
+		// Arrange
+		sut := repository.New()
+
+		// Act
+		customFonts, err := sut.AddUTF8FontFromBytes("family", "invalid", []byte(``)).Load()
+
+		// Assert
+		assert.Nil(t, err)
+		assert.Len(t, customFonts, 0)
+	})
+
+	t.Run("when fontstyle bytes is nil, should not add value", func(t *testing.T) {
+		// Arrange
+		sut := repository.New()
+
+		// Act
+		customFonts, err := sut.AddUTF8FontFromBytes("family", fontstyle.Bold, nil).Load()
+
+		// Assert
+		assert.Nil(t, err)
+		assert.Len(t, customFonts, 0)
+	})
+
+	t.Run("when fontstyle is valid, should not value", func(t *testing.T) {
+		// Arrange
+		sut := repository.New()
+		ttf, err := os.ReadFile(buildPath("/docs/assets/fonts/arial-unicode-ms.ttf"))
+		require.NoError(t, err)
+
+		// Act
+		customFonts, err := sut.AddUTF8FontFromBytes("family", fontstyle.Bold, ttf).Load()
+
+		// Assert
+		assert.Nil(t, err)
+		assert.Len(t, customFonts, 1)
+		assert.Equal(t, "family", customFonts[0].Family)
+		assert.Equal(t, fontstyle.Bold, customFonts[0].Style)
+		assert.Empty(t, customFonts[0].File)
+		assert.NotEmpty(t, customFonts[0].Bytes)
+	})
+}
+
 func buildPath(file string) string {
 	dir, err := os.Getwd()
 	if err != nil {