Added program to check Smith number (#6955)

added smith number program

src/test/java/com/thealgorithms/maths/SmithNumberTest.java

@@ -0,0 +1,22 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class SmithNumberTest {
+
+    @ParameterizedTest
+    @CsvSource({"4", "22", "121", "562", "985", "4937775"})
+    void positiveSmithNumbersTest(int n) {
+        assertTrue(SmithNumber.isSmithNumber(n));
+    }
+
+    @ParameterizedTest
+    @CsvSource({"2", "11", "100", "550", "999", "1234557"})
+    void negativeSmithNumbersTest(int n) {
+        assertFalse(SmithNumber.isSmithNumber(n));
+    }
+}