Add tests for SoundcloudCommentsExtractor to handle null next_href and empty comments

Author: Ecomont

extractor/src/test/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudCommentsExtractorTest.java

@@ -0,0 +1,100 @@
+package org.schabi.newpipe.extractor.services.soundcloud;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.schabi.newpipe.extractor.ServiceList.SoundCloud;
+
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.schabi.newpipe.extractor.ListExtractor.InfoItemsPage;
+import org.schabi.newpipe.extractor.Page;
+import org.schabi.newpipe.extractor.comments.CommentsExtractor;
+import org.schabi.newpipe.extractor.comments.CommentsInfoItem;
+import org.schabi.newpipe.extractor.exceptions.ExtractionException;
+import org.schabi.newpipe.extractor.services.DefaultSimpleExtractorTest;
+
+import java.io.IOException;
+
+public class SoundcloudCommentsExtractorTest {
+
+    /**
+     * Regression test for <a href="https://github.com/TeamNewPipe/NewPipeExtractor/issues/1243">
+     * issue #1243</a>: when the SoundCloud API returns {@code "next_href": null} (no more pages),
+     * a subsequent call to {@link CommentsExtractor#getPage(Page)} with a null URL must not throw
+     * {@link IllegalArgumentException} ("Page doesn't contain an URL"). Instead the extractor
+     * must return {@link InfoItemsPage#emptyPage()}.
+     *
+     * <p>The crash manifests during pagination: the last page of comments stores
+     * {@code new Page(null)} as the next page, and when Paging 3 tries to fetch it the
+     * exception propagates and kills the app.</p>
+     */
+    @Nested
+    class TrackWithComments extends DefaultSimpleExtractorTest<CommentsExtractor> {
+        // This track is known to reproduce issue #1243: it has comments, but when pagination
+        // exhausts the pages the API returns next_href=null, which previously caused a crash.
+        private static final String URL = "https://soundcloud.com/user-722618400/a-real-playa";
+
+        @Override
+        protected CommentsExtractor createExtractor() throws Exception {
+            return SoundCloud.getCommentsExtractor(URL);
+        }
+
+        /**
+         * The initial page must load successfully without throwing any exception.
+         */
+        @Test
+        void testGetInitialPageSucceeds() throws IOException, ExtractionException {
+            final InfoItemsPage<CommentsInfoItem> page = extractor().getInitialPage();
+            // The track has comments; we only assert the call itself does not throw
+            // and that the result is a valid (non-null) page.
+            assertTrue(page.getErrors().isEmpty(),
+                    "Expected no extractor errors on initial page");
+        }
+
+        /**
+         * Regression test for issue #1243: calling {@link CommentsExtractor#getPage(Page)} with a
+         * {@link Page} whose URL is null (which is what gets stored when {@code next_href} is
+         * absent in the API response) must return {@link InfoItemsPage#emptyPage()} rather than
+         * throw {@link IllegalArgumentException}.
+         */
+        @Test
+        void testGetPageWithNullUrlReturnsEmptyPage() throws IOException, ExtractionException {
+            final InfoItemsPage<CommentsInfoItem> page = extractor().getPage(new Page((String) null));
+            assertTrue(page.getItems().isEmpty(),
+                    "Expected empty items when page URL is null");
+            assertFalse(page.hasNextPage(),
+                    "Expected no next page when page URL is null");
+        }
+    }
+
+    /**
+     * Tests a SoundCloud track that has no comments.
+     *
+     * <p>Verifies that the extractor handles an empty collection gracefully:
+     * the initial page must load without error, return no items, and have no next page.</p>
+     */
+    @Nested
+    class TrackWithNoComments extends DefaultSimpleExtractorTest<CommentsExtractor> {
+        private static final String URL = "https://soundcloud.com/user285130010/jdkskls";
+
+        @Override
+        protected CommentsExtractor createExtractor() throws Exception {
+            return SoundCloud.getCommentsExtractor(URL);
+        }
+
+        /**
+         * The initial page must load successfully, return an empty items list,
+         * and report no next page.
+         */
+        @Test
+        void testGetInitialPageIsEmpty() throws IOException, ExtractionException {
+            final InfoItemsPage<CommentsInfoItem> page = extractor().getInitialPage();
+            assertTrue(page.getErrors().isEmpty(),
+                    "Expected no extractor errors on initial page");
+            assertTrue(page.getItems().isEmpty(),
+                    "Expected no comments for a track with no comments");
+            assertFalse(page.hasNextPage(),
+                    "Expected no next page for a track with no comments");
+        }
+    }
+}