Enhanced test library.xml with an entry not backed by a ZIM file

The test data was modified so that support for catalog only mode
of kiwix-serve can be properly tested.

The effect of this change in the test data on the library_server unit
test demonstrates that although the new entry does not appear in the
catalog (for example, no catalog_v2_entries* test cases were affected)
the category and language of this ghost entry slipped into the
observable output.

test/data/library.xml

@@ -51,4 +51,21 @@
         size="556"
         favicon="faviconMimeType_attribute_is_absent"
       ></book>
+  <book
+        id="inaccessiblezim"
+        path="./nosuchzimfile.zim"
+        url="https://github.com/kiwix/libkiwix/raw/master/test/data/nosuchzimfile.zim"
+        title="Catalog of all catalogs"
+        description="Testing that running kiwix-serve without access to ZIM files doesn't lead to a catastrophe"
+        language="cat"
+        creator="Catherine of Catalonia"
+        publisher="Caterpillar"
+        date="2025-09-04"
+        name="catalog_of_all_catalogs"
+        tags="unittest;_category:cats"
+        articleCount="12107"
+        mediaCount="8"
+        size="20250904"
+        favicon="Catania Cathedral"
+      ></book>
 </library>

test/library_server.cpp

@@ -560,6 +560,15 @@ TEST_F(LibraryServerTest, catalog_v2_categories)
   <title>List of categories</title>
   <updated>YYYY-MM-DDThh:mm:ssZ</updated>
 
+  <entry>
+    <title>cats</title>
+    <link rel="subsection"
+          href="/ROOT%23%3F/catalog/v2/entries?category=cats"
+          type="application/atom+xml;profile=opds-catalog;kind=acquisition"/>
+    <updated>YYYY-MM-DDThh:mm:ssZ</updated>
+    <id>12345678-90ab-cdef-1234-567890abcdef</id>
+    <content type="text">All entries with category of 'cats'.</content>
+  </entry>
   <entry>
     <title>jazz</title>
     <link rel="subsection"
@@ -602,6 +611,16 @@ TEST_F(LibraryServerTest, catalog_v2_languages)
   <title>List of languages</title>
   <updated>YYYY-MM-DDThh:mm:ssZ</updated>
 
+  <entry>
+    <title>català</title>
+    <dc:language>cat</dc:language>
+    <thr:count>1</thr:count>
+    <link rel="subsection"
+          href="/ROOT%23%3F/catalog/v2/entries?lang=cat"
+          type="application/atom+xml;profile=opds-catalog;kind=acquisition"/>
+    <updated>YYYY-MM-DDThh:mm:ssZ</updated>
+    <id>12345678-90ab-cdef-1234-567890abcdef</id>
+  </entry>
   <entry>
     <title>English</title>
     <dc:language>eng</dc:language>
@@ -1332,6 +1351,7 @@ TEST_F(LibraryServerTest, no_name_mapper_catalog_v2_individual_entry_access)
   "        <div class=\"kiwixNav__select\">\n" \
   "          <select name=\"lang\" id=\"languageFilter\" class='kiwixNav__kiwixFilter filter' form=\"kiwixSearchForm\">\n" \
   "            <option value=\"\" selected>All languages</option>\n" \
+  "            <option value=\"cat\">català</option>\n" \
   "            <option value=\"eng\"" SELECTED_ENG ">English</option>\n" \
   "            <option value=\"fra\">français</option>\n" \
   "            <option value=\"rus\">русский</option>\n" \
@@ -1340,6 +1360,7 @@ TEST_F(LibraryServerTest, no_name_mapper_catalog_v2_individual_entry_access)
   "        <div class=\"kiwixNav__select\">\n" \
   "          <select name=\"category\" id=\"categoryFilter\" class='kiwixNav__kiwixFilter filter' form=\"kiwixSearchForm\">\n" \
   "            <option value=\"\">All categories</option>\n" \
+  "            <option value=\"cats\">Cats</option>\n" \
   "            <option value=\"jazz\">Jazz</option>\n" \
   "            <option value=\"wikipedia\">Wikipedia</option>\n" \
   "          </select>\n" \

test/manager.cpp

@@ -88,6 +88,7 @@ TEST(Manager, reload)
   manager.reload({ "./test/library.xml" });
   EXPECT_EQ(lib->getBooksIds(), (kiwix::Library::BookIdCollection{
         "charlesray",
+        "inaccessiblezim",
         "raycharles",
         "raycharles_uncategorized"
   }));
@@ -95,12 +96,14 @@ TEST(Manager, reload)
   lib->removeBookById("raycharles");
   EXPECT_EQ(lib->getBooksIds(), (kiwix::Library::BookIdCollection{
         "charlesray",
+        "inaccessiblezim",
         "raycharles_uncategorized"
   }));
 
   manager.reload({ "./test/library.xml" });
   EXPECT_EQ(lib->getBooksIds(), kiwix::Library::BookIdCollection({
         "charlesray",
+        "inaccessiblezim",
         "raycharles",
         "raycharles_uncategorized"
   }));