Remove null test

Author: nguyentanphat8694

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

@@ -16,32 +16,6 @@ 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 testEditDistanceNullValue() {
-        assertThrows(NullPointerException.class, () -> { EditDistance.editDistance(null, "hello"); });
-        assertThrows(NullPointerException.class, () -> { EditDistance.editDistance("hello", null); });
-        assertThrows(NullPointerException.class, () -> { EditDistance.editDistance(null, null); });
-    }
-
     @Test
     public void testEditDistanceBothEmptyStrings() {
         assertEquals(0, EditDistance.editDistance("", ""));