added parameterized test class to test multiple inputs

junit-demo/src/main/java/com/calculator/Calculator.java

 package com.calculator;
 
+import java.util.Collection;
+
 public class Calculator {
 
     public int add(int a, int b) {

junit-demo/src/test/java/com/calculator/AnnotatedTestRunner.java

@@ -4,7 +4,7 @@ import org.junit.runner.RunWith;
 import org.junit.runners.Suite;
 
 @RunWith(Suite.class)
-@Suite.SuiteClasses({CalculatorTest.class, SampleTestClass.class, TestResultClass.class})
+@Suite.SuiteClasses(TestSuite.class)
 public class AnnotatedTestRunner {
 
 }

junit-demo/src/test/java/com/calculator/ParameterizedCalculatorTest.java

+package com.calculator;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static org.junit.Assert.assertEquals;
+
+@RunWith(Parameterized.class)
+public class ParameterizedCalculatorTest {
+
+    Calculator paramCalc;
+    int firstVal;
+    int secondVal;
+    int expectedSum;
+
+    @Before
+    public void init() {
+        paramCalc = new Calculator();
+    }
+
+    public ParameterizedCalculatorTest(int firstVal, int secondVal, int expectedSum) {
+        super();
+        this.firstVal = firstVal;
+        this.secondVal = secondVal;
+        this.expectedSum = expectedSum;
+    }
+
+    @Parameterized.Parameters
+    public static Collection sumValues() {
+        return Arrays.asList(new Object[][] {
+                {2, 2, 4},
+                {4, 4, 8},
+                {3, 4, 7},
+                {10, 10, 20}
+        });
+    }
+
+    @Test
+    public void testSumValues() {
+        System.out.println("Sum of " + firstVal + " + " + secondVal + ": " + expectedSum);
+        assertEquals(expectedSum, paramCalc.add(firstVal, secondVal));
+    }
+}

junit-demo/src/test/java/com/calculator/TestRunner.java

@@ -6,7 +6,7 @@ import org.junit.runner.notification.Failure;
 
 public class TestRunner {
     public static void main(String[] args) {
-        Result result = JUnitCore.runClasses(SampleTestClass.class);
+        Result result = JUnitCore.runClasses(TestSuite.class);
         for (Failure failure : result.getFailures()) {
             System.out.println(failure.toString());
         }

junit-demo/src/test/java/com/calculator/TestSuite.java

+package com.calculator;
+
+import org.junit.runner.RunWith;
+import org.junit.runners.Suite;
+
+@RunWith(Suite.class)
+@Suite.SuiteClasses({CalculatorTest.class, TestResultClass.class, SampleTestClass.class,
+        ParameterizedCalculatorTest.class})
+public class TestSuite {
+}