Added add function to the ComplexNumber Object

src/main/java/com/ugsbo/complexnumcalc/ComplexNumber.java

@@ -56,4 +56,22 @@ public class ComplexNumber {
         }
     }
 
+    /**
+     * Adds two complex Numbers together.
+     * 
+     * @param addend The complex Number.
+     * @return The result of adding the two complex Numbers together, as a conplex
+     *         Number.
+     */
+    public ComplexNumber add(ComplexNumber addend) {
+        Double sumRealPart, sumImaginaryPart;
+
+        sumRealPart = this.realPart + addend.realPart;
+        sumImaginaryPart = this.imaginaryPart + addend.imaginaryPart;
+
+        ComplexNumber sum = new ComplexNumber(sumRealPart, sumImaginaryPart);
+
+        return sum;
+    }
+
 }

src/test/java/com/ugsbo/complexnumcalc/AddComplexNumbersTest.java

@@ -0,0 +1,30 @@
+package com.ugsbo.complexnumcalc;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class AddComplexNumbersTest {
+
+    @Test
+    public void addingTwoComplexNumbersWithoutImaginaryPart() {
+        ComplexNumber firstAddend = new ComplexNumber(Double.valueOf(5), Double.valueOf(0));
+        ComplexNumber SecoundAddend = new ComplexNumber(Double.valueOf(6), Double.valueOf(0));
+        ComplexNumber expected = new ComplexNumber(Double.valueOf(11), Double.valueOf(0));
+
+        ComplexNumber sum = firstAddend.add(SecoundAddend);
+
+        assertTrue("Dont sum to the sum", sum.equals(expected));
+    }
+
+    @Test
+    public void addingTwoComplexNumbersWithImaginaryPart() {
+        ComplexNumber firstAddend = new ComplexNumber(Double.valueOf(5), Double.valueOf(3));
+        ComplexNumber SecoundAddend = new ComplexNumber(Double.valueOf(6), Double.valueOf(4));
+        ComplexNumber expected = new ComplexNumber(Double.valueOf(11), Double.valueOf(7));
+
+        ComplexNumber sum = firstAddend.add(SecoundAddend);
+
+        assertTrue("Dont sum to the sum", sum.equals(expected));
+    }
+}