added second test updated to junit5

test/de/hftstuttgart/ip2/CalculatorSecondTest.java

+package de.hftstuttgart.ip2;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class CalculatorSecondTest {
+
+    private Calculator calculator = new Calculator();
+
+    @Test
+    public void add2() throws Exception {
+        assertEquals(5, calculator.add(2, 3), 0.1);
+    }
+
+    @Test
+    public void sub2() throws Exception {
+        assertEquals(-1, calculator.sub(2, 3), 0.1);
+    }
+
+    @Test
+    public void mult2() throws Exception {
+        assertEquals(15, calculator.mult(5, 2), 0.1);
+    }
+
+    @Test
+    public void div2() throws Exception {
+        assertEquals(5, calculator.div(15, 3), 0.1);
+    }
+
+    @Test
+    public void sum2() throws Exception {
+        assertEquals(12, calculator.sum(3, 4, 5), 0.1);
+    }
+
+}