test(rewrite): add unit test for referer rewrite function

internal/reader/rewrite/referer_override_test.go

@@ -0,0 +1,67 @@
+// SPDX-FileCopyrightText: Copyright The Miniflux Authors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package rewrite // import "miniflux.app/v2/internal/reader/rewrite"
+
+import (
+	"testing"
+)
+
+func TestGetRefererForURL(t *testing.T) {
+	testCases := []struct {
+		name     string
+		url      string
+		expected string
+	}{
+		{
+			name:     "Weibo Image URL",
+			url:      "https://wx1.sinaimg.cn/large/example.jpg",
+			expected: "https://weibo.com",
+		},
+		{
+			name:     "Pixiv Image URL",
+			url:      "https://i.pximg.net/img-master/example.jpg",
+			expected: "https://www.pixiv.net",
+		},
+		{
+			name:     "SSPai CDN URL",
+			url:      "https://cdnfile.sspai.com/example.png",
+			expected: "https://sspai.com",
+		},
+		{
+			name:     "Instagram CDN URL",
+			url:      "https://scontent-sjc3-1.cdninstagram.com/example.jpg",
+			expected: "https://www.instagram.com",
+		},
+		{
+			name:     "Piokok URL",
+			url:      "https://sp1.piokok.com/example.jpg",
+			expected: "https://sp1.piokok.com",
+		},
+		{
+			name:     "Weibo Video URL",
+			url:      "https://f.video.weibocdn.com/example.mp4",
+			expected: "https://weibo.com",
+		},
+		{
+			name:     "HelloGithub Image URL",
+			url:      "https://img.hellogithub.com/example.png",
+			expected: "https://hellogithub.com",
+		},
+		{
+			name:     "Non-matching URL",
+			url:      "https://example.com/image.jpg",
+			expected: "",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := GetRefererForURL(tc.url)
+			if result != tc.expected {
+				t.Errorf("GetRefererForURL(%s): expected %s, got %s",
+					tc.url, tc.expected, result)
+			}
+		})
+	}
+}