Add requested changes.

Author: FireMasterK

extractor/src/main/java/org/schabi/newpipe/extractor/stream/StreamExtractor.java

@@ -207,11 +207,11 @@ public boolean isUploaderVerified() throws ParsingException {
      * The subscriber count of the uploader.
      * If the subscriber count is not implemented, or is unavailable, return <code>-1</code>.
      *
-     * @return the subscriber count of the uploader or -1 if not available
+     * @return the subscriber count of the uploader or {@value UNKNOWN_SUBSCRIBER_COUNT} if not available
      * @throws ParsingException
      */
     public long getUploaderSubscriberCount() throws ParsingException {
-        return -1;
+        return UNKNOWN_SUBSCRIBER_COUNT;
     }
 
     /**

extractor/src/test/java/org/schabi/newpipe/extractor/services/DefaultStreamExtractorTest.java

@@ -34,6 +34,7 @@
 import static org.schabi.newpipe.extractor.ExtractorAsserts.assertIsSecureUrl;
 import static org.schabi.newpipe.extractor.ExtractorAsserts.assertIsValidUrl;
 import static org.schabi.newpipe.extractor.services.DefaultTests.defaultTestListOfItems;
+import static org.schabi.newpipe.extractor.stream.StreamExtractor.UNKNOWN_SUBSCRIBER_COUNT;
 
 /**
  * Test for {@link StreamExtractor}
@@ -45,7 +46,7 @@ public abstract class DefaultStreamExtractorTest extends DefaultExtractorTest<St
     public abstract String expectedUploaderName();
     public abstract String expectedUploaderUrl();
     public boolean expectedUploaderVerified() { return false; }
-    public long expectedUploaderSubscriberCountAtLeast() { return -1; }
+    public long expectedUploaderSubscriberCountAtLeast() { return UNKNOWN_SUBSCRIBER_COUNT; }
     public String expectedSubChannelName() { return ""; } // default: there is no subchannel
     public String expectedSubChannelUrl() { return ""; } // default: there is no subchannel
     public boolean expectedDescriptionIsEmpty() { return false; } // default: description is not empty
@@ -109,7 +110,11 @@ public void testUploaderVerified() throws Exception {
     @Test
     @Override
     public void testSubscriberCount() throws Exception {
-        assertGreaterOrEqual(expectedUploaderSubscriberCountAtLeast(), extractor().getUploaderSubscriberCount());
+        if (expectedUploaderSubscriberCountAtLeast() == UNKNOWN_SUBSCRIBER_COUNT) {
+            assertEquals(UNKNOWN_SUBSCRIBER_COUNT, extractor().getUploaderSubscriberCount());
+        } else {
+            assertGreaterOrEqual(expectedUploaderSubscriberCountAtLeast(), extractor().getUploaderSubscriberCount());
+        }
     }
 
     @Test