[duplicated subtitle] Add unit tests for SubtitleDeduplicator in SubtitleDeduplicatorTest.java.

Author: TransZAllen

extractor/src/test/java/org/schabi/newpipe/extractor/utils/SubtitleDeduplicatorTest.java

@@ -0,0 +1,98 @@
+package org.schabi.newpipe.extractor.utils;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+public class SubtitleDeduplicatorTest {
+
+    @Test
+    public void deduplicate_exactDuplicateEntries_shouldRemoveDuplicate() {
+        String input =
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">Hello</p>\n" +
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">Hello</p>";
+
+        String output = SubtitleDeduplicator.deduplicateContent(input);
+
+        String expected =
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">Hello</p>";
+
+        // The `strip()` method is used here to remove the trailing
+        // newline character (\n, outside of <p> tags) at the end of the `output`.
+        // Removing this (\n) does not affect the TTML subtitle paragraphs,
+        // as only the content within <p> tags is considered valid for subtitles.
+        assertEquals(expected, output.strip());
+    }
+
+    @Test
+    public void deduplicate_sameTimeDifferentText_shouldNotDeduplicate() {
+        String input =
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">Hello</p>\n" +
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">World</p>";
+
+        String output = SubtitleDeduplicator.deduplicateContent(input);
+
+        String expected = input;
+
+        assertEquals(expected, output);
+    }
+
+    @Test
+    public void deduplicate_sameTextDifferentTime_shouldNotDeduplicate() {
+        String input =
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">Hello</p>\n" +
+            "<p begin=\"00:00:02.000\" end=\"00:00:03.000\">Hello</p>";
+
+        String output = SubtitleDeduplicator.deduplicateContent(input);
+
+        String expected = input;
+
+        assertEquals(expected, output);
+    }
+
+    @Test
+    public void containsDuplicatedEntries_exactDuplicate_shouldReturnTrue() {
+        String input =
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">Hello</p>\n" +
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">Hello</p>";
+
+        assertTrue(SubtitleDeduplicator.containsDuplicatedEntries(input));
+    }
+
+    @Test
+    public void containsDuplicatedEntries_noDuplicate_shouldReturnFalse() {
+        String input =
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">Hello</p>\n" +
+            "<p begin=\"00:00:02.000\" end=\"00:00:03.000\">World</p>";
+
+        assertFalse(SubtitleDeduplicator.containsDuplicatedEntries(input));
+    }
+
+    @Test
+    public void containsDuplicatedEntries_normalizeLeadingAndTrailingWhitespace_shouldConsiderAsSame() {
+        // Note:
+        // This test verifies that the deduplication logic normalizes
+        // leading and trailing whitespace, and considers the content
+        // as the same after this normalization, without modifying
+        // the original subtitle content.
+        String input =
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">  Hello world  </p>\n" +
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">Hello world</p>";
+        assertTrue(SubtitleDeduplicator.containsDuplicatedEntries(input));
+    }
+
+    @Test
+    public void containsDuplicatedEntries_normalizeMultipleSpaces_shouldConsiderAsSingleSpace() {
+        // Note:
+        // This test verifies that the deduplication logic normalizes
+        // multiple consecutive spaces into a single space,
+        // considering the content as the same after this normalization,
+        // without modifying the original subtitle content.
+        String input =
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">Hello    world</p>\n" +
+            "<p begin=\"00:00:01.000\" end=\"00:00:02.000\">Hello world</p>";
+        assertTrue(SubtitleDeduplicator.containsDuplicatedEntries(input));
+    }
+}