tests for download func

downloadImage_test.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestDownloadImage(t *testing.T) {
+	downloader := RealImageDownloader{}
+
+	// Create a temporary directory for testing
+	tempDir := t.TempDir()
+
+	// Test case: Successful download
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte("test image content"))
+	}))
+	defer server.Close()
+
+	filename := "test_image.jpg"
+	err := downloader.DownloadImage(server.URL, tempDir, filename)
+	if err != nil {
+		t.Errorf("expected no error, got %v", err)
+	}
+
+	// Check if the file was created
+	filePath := filepath.Join(tempDir, filename)
+	if _, err := os.Stat(filePath); os.IsNotExist(err) {
+		t.Errorf("expected file %s to be created, but it does not exist", filePath)
+	}
+
+	// Check the file content
+	file, err := os.Open(filePath)
+	if err != nil {
+		t.Errorf("expected no error opening file, got %v", err)
+	}
+	defer file.Close()
+
+	content, err := io.ReadAll(file)
+	if err != nil {
+		t.Errorf("expected no error reading file, got %v", err)
+	}
+
+	expectedContent := "test image content"
+	if string(content) != expectedContent {
+		t.Errorf("expected file content %s, got %s", expectedContent, string(content))
+	}
+}