Add unit test for com.thealgorithms.dynamicprogramming.EditDistance

Author: nguyentanphat8694

src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java

@@ -1,15 +1,152 @@
 package com.thealgorithms.dynamicprogramming;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
 
+import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertAll;
+
 public class EditDistanceTest {
 
     @ParameterizedTest
     @CsvSource({"'', '', 0", "'abc', '', 3", "'', 'abcd', 4", "'same', 'same', 0", "'a', 'b', 1", "'abc', 'abd', 1"})
     void testMinDistance(String str1, String str2, int expected) {
         assertEquals(expected, EditDistance.minDistance(str1, str2));
     }
+
+    @Test
+    void testEditDistanceStringNull() {
+        assertThrows(NullPointerException.class, () -> {
+            EditDistance.editDistance(null, "abc");
+        });
+        assertThrows(NullPointerException.class, () -> {
+            EditDistance.editDistance("abc", null);
+        });
+        assertThrows(NullPointerException.class, () -> {
+            EditDistance.editDistance(null, null);
+        });
+    }
+
+    @Test
+    void testEditDistanceStringEmpty() {
+        int expected = 0;
+        assertEquals(0, EditDistance.editDistance("", ""));
+        String s1 = "abc";
+        expected = s1.length();
+        assertEquals(expected, EditDistance.editDistance(s1, ""));
+        String s2 = "aa";
+        expected = s2.length();
+        assertEquals(expected, EditDistance.editDistance("", s2));
+    }
+
+    @Test
+    void testEditDistance_NullValue() {
+        assertThrows(NullPointerException.class, () -> {
+            EditDistance.editDistance(null, "hello");
+        });
+        assertThrows(NullPointerException.class, () -> {
+            EditDistance.editDistance("hello", null);
+        });
+        assertThrows(NullPointerException.class, () -> {
+            EditDistance.editDistance(null, null);
+        });
+    }
+
+    @Test
+    public void testEditDistance_BothEmptyStrings() {
+        assertEquals(0, EditDistance.editDistance("", ""));
+    }
+
+    @Test
+    public void testEditDistance_OneEmptyString() {
+        assertEquals(5, EditDistance.editDistance("", "hello"));
+        assertEquals(7, EditDistance.editDistance("worldly", ""));
+    }
+
+    @Test
+    public void testEditDistance_OneEmptyString_Memoization() {
+        int[][] storage = new int[1][6];
+        ;
+        assertAll("String assertions",
+                () -> assertEquals(5, EditDistance.editDistance("", "hello", storage)),
+                () -> assertEquals(0, storage[0][0]),
+                () -> assertEquals(0, storage[0][1]),
+                () -> assertEquals(0, storage[0][2]),
+                () -> assertEquals(0, storage[0][3]),
+                () -> assertEquals(0, storage[0][4]),
+                () -> assertEquals(5, storage[0][5])
+        );
+    }
+
+    @Test
+    public void testEditDistance_EqualStrings() {
+        assertEquals(0, EditDistance.editDistance("test", "test"));
+        assertEquals(0, EditDistance.editDistance("abc", "abc"));
+    }
+
+    @Test
+    public void testEditDistance_EqualStrings_Memoization() {
+        int[][] storage = new int[4][4];
+        assertAll("String assertions",
+                () -> assertEquals(0, EditDistance.editDistance("abc", "abc", storage)),
+                () -> assertEquals(0, storage[0][0]),
+                () -> assertEquals(0, storage[0][1]),
+                () -> assertEquals(0, storage[0][2]),
+                () -> assertEquals(0, storage[0][3]),
+                () -> assertEquals(0, storage[1][0]),
+                () -> assertEquals(0, storage[1][1]),
+                () -> assertEquals(0, storage[1][2]),
+                () -> assertEquals(0, storage[1][3]),
+                () -> assertEquals(0, storage[2][0]),
+                () -> assertEquals(0, storage[2][1]),
+                () -> assertEquals(0, storage[2][2]),
+                () -> assertEquals(0, storage[2][3]),
+                () -> assertEquals(0, storage[3][0]),
+                () -> assertEquals(0, storage[3][1]),
+                () -> assertEquals(0, storage[3][2]),
+                () -> assertEquals(0, storage[3][3])
+        );
+    }
+
+    @Test
+    public void testEditDistance_OneCharacterDifference() {
+        assertEquals(1, EditDistance.editDistance("cat", "bat"));
+        assertEquals(1, EditDistance.editDistance("cat", "cats"));
+        assertEquals(1, EditDistance.editDistance("cats", "cat"));
+    }
+
+    @Test
+    public void testEditDistance_OneCharacterDifference_Memoization() {
+        int[][] storage = new int[3][3];
+        assertAll("All assertions",
+                () -> assertEquals(1, EditDistance.editDistance("at", "it", storage)),
+                () -> assertEquals(0, storage[0][0]),
+                () -> assertEquals(1, storage[0][1]),
+                () -> assertEquals(2, storage[0][2]),
+                () -> assertEquals(1, storage[1][0]),
+                () -> assertEquals(0, storage[1][1]),
+                () -> assertEquals(1, storage[1][2]),
+                () -> assertEquals(2, storage[2][0]),
+                () -> assertEquals(1, storage[2][1]),
+                () -> assertEquals(1, storage[2][2])
+        );
+    }
+
+    @Test
+    public void testEditDistance_GeneralCases() {
+        assertEquals(3, EditDistance.editDistance("kitten", "sitting"));
+        assertEquals(2, EditDistance.editDistance("flaw", "lawn"));
+        assertEquals(5, EditDistance.editDistance("intention", "execution"));
+    }
+
+    @Test
+    public void testEditDistance_GeneralCases_Memoization() {
+        int[][] storage = new int[7][8];
+        assertEquals(3, EditDistance.editDistance("kitten", "sitting", storage));
+        assertAll("All assertions",
+                () -> assertEquals(0, storage[0][0]),
+                () -> assertEquals(3, storage[6][7])
+        );
+    }
 }