BAEL-2347: Added test examples for Coupound Assignment Operators.

core-java-lang/src/test/java/com/baeldung/compoundoperators/CompoundOperatorsTest.java

@@ -0,0 +1,111 @@
+package com.baeldung.compoundoperators;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class CompoundOperatorsTest {
+
+    @Test
+    public void whenAssignmentOperatorIsUsed_thenValueIsAssigned() {
+        int x = 5;
+
+        assertEquals(5, x);
+    }
+
+    @Test
+    public void whenCompoundAssignmentUsed_thenSameAsSimpleAssignment() {
+        int a = 3, b = 3, c = -2;
+        a = a * c; // Simple assignment operator
+        b *= c; // Compound assignment operator
+
+        assertEquals(a, b);
+    }
+
+    @Test
+    public void whenAssignmentOperatorIsUsed_thenValueIsReturned() {
+        long x = 5;
+        long y = (x=3);
+
+        assertEquals(3, y);
+        assertEquals(y, x);
+    }
+
+    @Test
+    public void whenCompoundOperatorsAreUsed_thenOperationsArePerformedAndAssigned() {
+        //Simple assignment
+        int x = 5; //x is 5
+
+        //Incrementation
+        x += 5; //x is 10
+        assertEquals(10, x);
+
+        //Decrementation
+        x -= 2; //x is 8
+        assertEquals(8, x);
+
+        //Multiplication
+        x *= 2; //x is 16
+        assertEquals(16, x);
+
+        //Division
+        x /= 4; //x is 4
+        assertEquals(4, x);
+
+        //Modulus
+        x %= 3; //x is 1
+        assertEquals(1, x);
+
+
+        //Binary AND
+        x &= 4; //x is 0
+        assertEquals(0, x);
+
+        //Binary exclusive OR
+        x ^= 4; //x is 4
+        assertEquals(4, x);
+
+        //Binary inclusive OR
+        x |= 8; //x is 12
+        assertEquals(12, x);
+
+
+        //Binary Left Shift
+        x <<= 2; //x is 48
+        assertEquals(48, x);
+
+        //Binary Right Shift
+        x >>= 2; //x is 12
+        assertEquals(12, x);
+
+        //Shift right zero fill
+        x >>>= 1; //x is 6
+        assertEquals(6, x);
+    }
+
+    @Test(expected = NullPointerException.class)
+    public void whenArrayIsNull_thenThrowNullException() {
+        int[] numbers = null;
+
+        //Trying Incrementation
+        numbers[2] += 5;
+    }
+
+    @Test(expected = ArrayIndexOutOfBoundsException.class)
+    public void whenArrayIndexNotCorrect_thenThrowArrayIndexException() {
+        int[] numbers = {0, 1};
+
+        //Trying Incrementation
+        numbers[2] += 5;
+    }
+
+    @Test
+    public void whenArrayIndexIsCorrect_thenPerformOperation() {
+        int[] numbers = {0, 1};
+
+        //Incrementation
+        numbers[1] += 5;
+        assertEquals(6, numbers[1]);
+    }
+
+}