diff --git a/app/core/src/test/java/org/apache/pdfbox/examples/util/ConnectedInputStreamTest.java b/app/core/src/test/java/org/apache/pdfbox/examples/util/ConnectedInputStreamTest.java
new file mode 100644
index 000000000..48d8b11a4
--- /dev/null
+++ b/app/core/src/test/java/org/apache/pdfbox/examples/util/ConnectedInputStreamTest.java
@@ -0,0 +1,86 @@
+package org.apache.pdfbox.examples.util;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.nio.charset.StandardCharsets;
+
+import org.junit.jupiter.api.Test;
+import org.mockito.InOrder;
+
+class ConnectedInputStreamTest {
+
+    @Test
+    void delegates_read_skip_available_mark_reset_and_markSupported() throws IOException {
+        byte[] data = "hello world".getBytes(StandardCharsets.UTF_8);
+        ByteArrayInputStream base = new ByteArrayInputStream(data);
+        HttpURLConnection con = mock(HttpURLConnection.class);
+
+        ConnectedInputStream cis = new ConnectedInputStream(con, base);
+
+        // mark support
+        assertTrue(cis.markSupported());
+
+        // available at start
+        assertEquals(data.length, cis.available());
+
+        // read single byte
+        int first = cis.read();
+        assertEquals('h', first);
+
+        // mark here
+        cis.mark(100);
+
+        // read next 4 bytes with read(byte[])
+        byte[] buf4 = new byte[4];
+        int n4 = cis.read(buf4);
+        assertEquals(4, n4);
+        assertArrayEquals("ello".getBytes(StandardCharsets.UTF_8), buf4);
+
+        // read next 1 byte with read(byte[], off, len)
+        byte[] one = new byte[1];
+        int n1 = cis.read(one, 0, 1);
+        assertEquals(1, n1);
+        assertEquals((int) ' ', one[0] & 0xFF);
+
+        // reset to mark and re-read the same 5 bytes ("ello ")
+        cis.reset();
+        byte[] again5 = new byte[5];
+        int n5 = cis.read(again5, 0, 5);
+        assertEquals(5, n5);
+        assertArrayEquals("ello ".getBytes(StandardCharsets.UTF_8), again5);
+
+        // skip one byte ('w')
+        long skipped = cis.skip(1);
+        assertEquals(1, skipped);
+
+        // remaining should be "orld" (4 bytes)
+        assertEquals(4, cis.available());
+        byte[] rest = new byte[4];
+        assertEquals(4, cis.read(rest));
+        assertArrayEquals("orld".getBytes(StandardCharsets.UTF_8), rest);
+
+        // end of stream
+        assertEquals(-1, cis.read());
+        cis.close();
+        verify(con).disconnect();
+    }
+
+    @Test
+    void close_closes_stream_before_disconnect() throws IOException {
+        InputStream is = mock(InputStream.class);
+        HttpURLConnection con = mock(HttpURLConnection.class);
+
+        ConnectedInputStream cis = new ConnectedInputStream(con, is);
+        cis.close();
+
+        InOrder inOrder = inOrder(is, con);
+        inOrder.verify(is).close();
+        inOrder.verify(con).disconnect();
+        inOrder.verifyNoMoreInteractions();
+    }
+}