Fix style: Add final newlines to string files

Author: Rosander0

src/test/java/com/thealgorithms/strings/LongestCommonSubstringTest.java

@@ -1,35 +1,34 @@
 package com.thealgorithms.strings;
 
-import java.util.stream.Stream;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import org.junit.jupiter.api.Test;
 
-import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.MethodSource;
+public class LongestCommonSubstringTest {
 
-public final class LongestCommonSubstringTest {
+    @Test
+    public void testNullOrEmptyInputs() {
+        assertEquals("", LongestCommonSubstring.longestCommonSubstring(null, "abc"));
+        assertEquals("", LongestCommonSubstring.longestCommonSubstring("abc", null));
+        assertEquals("", LongestCommonSubstring.longestCommonSubstring("", "abc"));
+        assertEquals("", LongestCommonSubstring.longestCommonSubstring("abc", ""));
+    }
 
-    private record TestData(String a, String b, String expected) {
+    @Test
+    public void testNormalSubstrings() {
+        assertEquals("cde", LongestCommonSubstring.longestCommonSubstring("abcdef", "zcdemf"));
+        assertEquals("abc", LongestCommonSubstring.longestCommonSubstring("abc", "abc"));
+        assertEquals("cdef", LongestCommonSubstring.longestCommonSubstring("abcdef", "cdefgh"));
     }
 
-    private static Stream<TestData> testLongestCommonSubstring() {
-        return Stream.of(
-            new TestData(null, "abc", ""),
-            new TestData("abc", null, ""),
-            new TestData("", "abc", ""),
-            new TestData("abc", "", ""),
-            new TestData("abcdef", "zcdemf", "cde"),
-            new TestData("abc", "abc", "abc"),
-            new TestData("abc", "xyz", ""),
-            new TestData("abcdef", "cdefgh", "cdef"),
-            new TestData("a", "a", "a"),
-            new TestData("abcXdef", "abcYdef", "abc")
-        );
+    @Test
+    public void testSingleCharacterAndNoMatch() {
+        assertEquals("a", LongestCommonSubstring.longestCommonSubstring("a", "a"));
+        assertEquals("", LongestCommonSubstring.longestCommonSubstring("abc", "xyz"));
     }
 
-    @ParameterizedTest
-    @MethodSource
-    void testLongestCommonSubstring(TestData testData) {
-        String actual = LongestCommonSubstring.longestCommonSubstring(testData.a(), testData.b());
-        Assertions.assertEquals(testData.expected(), actual);
+    @Test
+    public void testMultipleMatchesFirstLongest() {
+        // Keeps the first matched longest substring when lengths are tied
+        assertEquals("abc", LongestCommonSubstring.longestCommonSubstring("abcXdef", "abcYdef"));
     }
 }