Added tests for the `TimestampExtractor`

app/src/test/java/org/schabi/newpipe/util/external_communication/TimestampExtractorTest.java

@@ -0,0 +1,101 @@
+package org.schabi.newpipe.util.external_communication;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+import java.time.Duration;
+import java.util.Arrays;
+import java.util.List;
+import java.util.regex.Matcher;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.fail;
+
+@RunWith(Parameterized.class)
+public class TimestampExtractorTest {
+
+    @Parameterized.Parameter(0)
+    public Duration expected;
+
+    @Parameterized.Parameter(1)
+    public String stringToProcess;
+
+    @Parameterized.Parameters(name = "Expecting {0} for \"{1}\"")
+    public static List<Object[]> dataForTests() {
+        return Arrays.asList(new Object[][]{
+                // Simple valid values
+                {Duration.ofSeconds(1), "0:01"},
+                {Duration.ofSeconds(1), "00:01"},
+                {Duration.ofSeconds(1), "0:00:01"},
+                {Duration.ofSeconds(1), "00:00:01"},
+                {Duration.ofMinutes(1).plusSeconds(23), "1:23"},
+                {Duration.ofMinutes(1).plusSeconds(23), "01:23"},
+                {Duration.ofMinutes(1).plusSeconds(23), "0:01:23"},
+                {Duration.ofMinutes(1).plusSeconds(23), "00:01:23"},
+                {Duration.ofHours(1).plusMinutes(23).plusSeconds(45), "1:23:45"},
+                {Duration.ofHours(1).plusMinutes(23).plusSeconds(45), "01:23:45"},
+                // Check with additional text
+                {Duration.ofSeconds(1), "Wow 0:01 words"},
+                {Duration.ofMinutes(1).plusSeconds(23), "Wow 1:23 words"},
+                {Duration.ofSeconds(1), "Wow 0:01 words! 33:"},
+                {null, "Wow0:01 abc"},
+                {null, "Wow 0:01abc"},
+                {null, "Wow0:01abc"},
+                {null, "Wow0:01"},
+                {null, "0:01abc"},
+                // Boundary checks
+                {Duration.ofSeconds(0), "0:00"},
+                {Duration.ofHours(59).plusMinutes(59).plusSeconds(59), "59:59:59"},
+                {null, "60:59:59"},
+                {null, "60:59"},
+                {null, "0:60"},
+                // Format checks
+                {null, "000:0"},
+                {null, "123:01"},
+                {null, "123:123"},
+                {null, "2:123"},
+                {null, "2:3"},
+                {null, "1:2:3"},
+                {null, ":3"},
+                {null, "01:"},
+                {null, ":01"},
+                {null, "a:b:c"},
+                {null, "abc:def:ghj"},
+                {null, "::"},
+                {null, ":"},
+                {null, ""}
+        });
+    }
+
+    @Test
+    public void testExtract() {
+        final Matcher m = TimestampExtractor.TIMESTAMPS_PATTERN.matcher(this.stringToProcess);
+
+        if (!m.find()) {
+            if (expected == null) {
+                return;
+            }
+            fail("No match found but expected one");
+        }
+
+        final TimestampExtractor.TimestampMatchDTO timestampMatchDTO =
+                TimestampExtractor
+                        .getTimestampFromMatcher(m, this.stringToProcess);
+
+        if (timestampMatchDTO == null) {
+            if (expected == null) {
+                return;
+            }
+            fail("Result shouldn't be null");
+        } else if (expected == null) {
+            assertNull("Expected that the dto is null, but it isn't", timestampMatchDTO);
+            return;
+        }
+
+        final int actualSeconds = timestampMatchDTO.seconds();
+
+        assertEquals(expected.getSeconds(), actualSeconds);
+    }
+}