Add null event map test

DEVSIX-7418

Author: Dmitry Radchuk

kernel/src/main/java/com/itextpdf/kernel/pdf/function/PdfFunction.java

@@ -141,6 +141,15 @@ public void doActionNullDocumentTest() {
         AssertUtil.doesNotThrow(() -> closeEvent.doAction());
     }
 
+    @Test
+    public void doActionNullEventMapTest() throws IOException {
+        try (PdfDocument document = new DummyPdfDocument(new PdfReader(SOURCE_FOLDER + "hello.pdf"))) {
+            AssertUtil.doesNotThrow(() -> new FlushPdfDocumentEvent(document).doAction());
+            Assert.assertTrue(document.getDocumentInfo().getProducer()
+                    .contains("Apryse Group NV (no registered products)"));
+        }
+    }
+
     @Test
     public void flushEventAfterEachEventTest() throws IOException {
         String resourceInit = SOURCE_FOLDER + "hello.pdf";
@@ -157,6 +166,17 @@ public void flushEventAfterEachEventTest() throws IOException {
         }
     }
 
+    private static class DummyPdfDocument extends PdfDocument {
+
+        public DummyPdfDocument(PdfReader reader) {
+            super(reader);
+        }
+
+        public SequenceId getDocumentIdWrapper() {
+            return null;
+        }
+    }
+
     private static class TestProductEventProcessor implements ITextProductEventProcessor {
         private final String processorId;