refactor: move check if file exsits to provider

internal/http_test.go

@@ -0,0 +1,13 @@
+package internal
+
+import "testing"
+
+func TestGetRandomUserAgent(t *testing.T) {
+	t.Run("should return a random user agent", func(t *testing.T) {
+		userAgent := getRandomUserAgent()
+
+		if userAgent == "" {
+			t.Error("Expected user agent, got empty string")
+		}
+	})
+}

internal/provider/file.go

@@ -1,6 +1,10 @@
 package provider
 
-import "github.com/michalczmiel/batch-image-getter/internal"
+import (
+	"fmt"
+
+	"github.com/michalczmiel/batch-image-getter/internal"
+)
 
 type FileProvider struct {
 	path       string
@@ -15,6 +19,10 @@ func NewFileProvider(path string, fileSystem internal.FileSystem) Provider {
 }
 
 func (p *FileProvider) Links() ([]string, error) {
+	if !p.fileSystem.Exists(p.path) {
+		return nil, fmt.Errorf("file does not exist")
+	}
+
 	lines, err := p.fileSystem.ReadLines(p.path)
 	if err != nil {
 		return nil, err

internal/provider/file_test.go

@@ -0,0 +1,76 @@
+package provider
+
+import (
+	"io"
+	"testing"
+)
+
+type mockFileSystem struct{}
+
+func (m mockFileSystem) Exists(path string) bool {
+	return path == "images.txt"
+}
+
+func (m mockFileSystem) ReadLines(path string) ([]string, error) {
+	return []string{
+		"https://example.com/image1.jpg",
+		"-",
+		"\n",
+		"https://example.com/image2.jpg",
+		"https://example.com/image3.jpg",
+	}, nil
+}
+
+func (m mockFileSystem) WriteLines(path string, lines []string) error {
+	return nil
+}
+
+func (m mockFileSystem) CreateDirectory(path string) error {
+	return nil
+}
+
+func (m mockFileSystem) Save(body io.ReadCloser, path string) error {
+	return nil
+}
+
+func TestProviderLinks(t *testing.T) {
+	t.Run("should return error when file does not exist", func(t *testing.T) {
+		fileSystem := mockFileSystem{}
+
+		provider := NewFileProvider("non-existing-file.txt", fileSystem)
+
+		_, err := provider.Links()
+
+		if err == nil {
+			t.Fatal("Expected error, got nil")
+		}
+	})
+
+	t.Run("should return valid links from existing file", func(t *testing.T) {
+		fileSystem := mockFileSystem{}
+
+		provider := NewFileProvider("images.txt", fileSystem)
+
+		links, err := provider.Links()
+
+		if err != nil {
+			t.Error(err)
+		}
+
+		expectedLinks := []string{
+			"https://example.com/image1.jpg",
+			"https://example.com/image2.jpg",
+			"https://example.com/image3.jpg",
+		}
+
+		if len(links) != len(expectedLinks) {
+			t.Fatalf("Expected %d links, got %d", len(expectedLinks), len(links))
+		}
+
+		for i, link := range links {
+			if link != expectedLinks[i] {
+				t.Fatalf("Expected %s, got %s", expectedLinks[i], link)
+			}
+		}
+	})
+}