fix(image): tests

README.md

@@ -163,6 +163,33 @@ if err != nil {
 bimg.Write("new.jpg", newImage)
 ```
 
+#### Fluent interface
+
+```go
+buffer, err := bimg.Read("image.jpg")
+if err != nil {
+  fmt.Fprintln(os.Stderr, err)
+}
+
+image := bimg.NewImage(buffer)
+
+// first crop image
+_, err := image.CropByWidth(300)
+if err != nil {
+  fmt.Fprintln(os.Stderr, err)
+}
+
+// then flip it
+newImage, err := image.Flip()
+if err != nil {
+  fmt.Fprintln(os.Stderr, err)
+}
+
+// save the cropped and flipped image
+bimg.Write("new.jpg", newImage)
+```
+
+
 #### func  DetermineImageTypeName
 
 ```go

image.go

@@ -87,6 +87,12 @@ func (i *Image) Flip() ([]byte, error) {
 }
 
 // Flop the image about the horizontal X axis
+func (i *Image) Flop() ([]byte, error) {
+	options := Options{Flip: VERTICAL}
+	return i.Process(options)
+}
+
+// Convert image to another format
 func (i *Image) Convert(t ImageType) ([]byte, error) {
 	options := Options{Type: t}
 	return i.Process(options)

image_test.go

@@ -144,6 +144,37 @@ func TestImageMetadata(t *testing.T) {
 	}
 }
 
+func TestFluentInterface(t *testing.T) {
+	image := initImage("test.jpg")
+	_, err := image.CropByWidth(300)
+	if err != nil {
+		t.Errorf("Cannot process the image: %#v", err)
+	}
+
+	_, err = image.Flip()
+	if err != nil {
+		t.Errorf("Cannot process the image: %#v", err)
+	}
+
+	buf, err := image.Convert(PNG)
+	if err != nil {
+		t.Errorf("Cannot process the image: %#v", err)
+	}
+
+	data, _ := image.Metadata()
+	if data.Alpha != true {
+		t.Fatal("Invalid alpha channel")
+	}
+	if data.Size.Width != 300 {
+		t.Fatal("Invalid width size")
+	}
+	if data.Type != "png" {
+		t.Fatal("Invalid image type")
+	}
+
+	Write("fixtures/test_image_fluent_out.png", buf)
+}
+
 func initImage(file string) *Image {
 	buf, _ := Read(path.Join("fixtures", file))
 	return NewImage(buf)