Add longest common subsequence tests

src/test/java/com/williamfiset/algorithms/dp/LongestCommonSubsequenceTest.java

@@ -0,0 +1,47 @@
+package com.williamfiset.algorithms.dp;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+import com.google.common.primitives.Ints;
+import com.williamfiset.algorithms.utils.TestUtils;
+import org.junit.*;
+
+
+public class LongestCommonSubsequenceTest {
+
+    @Test
+    public void testSuccessfulLongestCommonSubsequence() {
+        char[] A = {'A', 'X', 'B', 'C', 'Y', 'S'};
+        char[] B = {'Z', 'A', 'Y', 'W', 'B', 'C'};
+
+        String lcs = LongestCommonSubsequence.lcs(A, B);
+
+        assertEquals("ABC", lcs);
+    }
+
+    @Test
+    public void testSuccessfulUnequalParametersLongestCommonSubsequence() {
+        char[] A = {'A'};
+        char[] B = {'Z', 'A', 'Y', 'W', 'B', 'C', 'X', 'B', 'C', 'Y', 'S'};
+
+        String lcs = LongestCommonSubsequence.lcs(A, B);
+
+        assertEquals("A", lcs);
+    }
+
+    @Test
+    public void testNullParametersLongestCommonSubsequence() {
+        String test = LongestCommonSubsequence.lcs(null, null);
+        assertNull(test);
+    }
+
+    @Test
+    public void testEmptyParametersLongestCommonSubsequence() {
+        char[] A = {'A', 'X', 'B', 'C', 'Y', 'S'};
+        char[] B = {};
+        String test = LongestCommonSubsequence.lcs(A, B);
+        assertNull(test);
+    }
+}