From 7479e7b5a04b921e6d0fa12d03b6fe1b0561bff7 Mon Sep 17 00:00:00 2001
From: priyank-sriv <priyank.srivastava@appdirect.com>
Date: Mon, 15 Jun 2020 19:27:30 +0530
Subject: [PATCH] unit test for empty and full buffer

---
 .../circularbuffer/CircularBuffer.java        |  7 +-----
 .../CircularBufferUnitTest.java               | 25 ++++++++++++++-----
 2 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/data-structures/src/main/java/com/baeldung/circularbuffer/CircularBuffer.java b/data-structures/src/main/java/com/baeldung/circularbuffer/CircularBuffer.java
index a74b480231..6f60621bc8 100644
--- a/data-structures/src/main/java/com/baeldung/circularbuffer/CircularBuffer.java
+++ b/data-structures/src/main/java/com/baeldung/circularbuffer/CircularBuffer.java
@@ -1,7 +1,7 @@
 package com.baeldung.circularbuffer;
 
 public class CircularBuffer<E> {
-    
+
     private static final int DEFAULT_CAPACITY = 8;
 
     private final int capacity;
@@ -18,11 +18,6 @@ public class CircularBuffer<E> {
         this.writeSequence = -1;
     }
 
-    /**
-     * Adds a new element to the buffer, if the buffer is not full
-     * @param element
-     * @return
-     */
     public boolean offer(E element) {
 
         if (!isFull()) {
diff --git a/data-structures/src/test/java/com/baeldung/circularbuffer/CircularBufferUnitTest.java b/data-structures/src/test/java/com/baeldung/circularbuffer/CircularBufferUnitTest.java
index 0809444901..801a46b45c 100644
--- a/data-structures/src/test/java/com/baeldung/circularbuffer/CircularBufferUnitTest.java
+++ b/data-structures/src/test/java/com/baeldung/circularbuffer/CircularBufferUnitTest.java
@@ -1,5 +1,8 @@
 package com.baeldung.circularbuffer;
 
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
@@ -9,7 +12,7 @@ public class CircularBufferUnitTest {
     private final String[] shapes = { "Circle", "Triangle", "Rectangle", "Square", "Rhombus", "Trapezoid", "Pentagon", "Pentagram", "Hexagon", "Hexagram" };
 
     @Test
-    public void givenCircularBuffer_WhenAnElementIsAddedAndRemoved_thenBufferIsEmpty() {
+    public void givenCircularBuffer_whenAnElementIsAddedAndRemoved_thenBufferIsEmpty() {
 
         int capacity = 2;
         CircularBuffer<String> buffer = new CircularBuffer<>(capacity);
@@ -18,26 +21,36 @@ public class CircularBufferUnitTest {
 
         buffer.offer("Rectangle");
 
-        assertEquals(false, buffer.isEmpty());
+        assertFalse(buffer.isEmpty());
         assertEquals(1, buffer.size());
 
         buffer.poll();
 
-        assertEquals(true, buffer.isEmpty());
+        assertTrue(buffer.isEmpty());
     }
 
     @Test
-    public void givenCircularBuffer_WhenElementsAreAddedToCapacity_thenBufferIsFull() {
+    public void givenCircularBuffer_whenFilledToCapacity_thenNoMoreElementsCanBeAdded() {
 
         int capacity = shapes.length;
         CircularBuffer<String> buffer = new CircularBuffer<>(capacity);
 
-        assertEquals(true, buffer.isEmpty());
+        assertTrue(buffer.isEmpty());
 
         for (String shape : shapes) {
             buffer.offer(shape);
         }
 
-        assertEquals(true, buffer.isFull());
+        assertTrue(buffer.isFull());
+        assertFalse(buffer.offer("Octagon"));
+    }
+
+    @Test
+    public void givenCircularBuffer_whenBufferIsEmpty_thenReturnsNull() {
+
+        CircularBuffer<String> buffer = new CircularBuffer<>(1);
+
+        assertTrue(buffer.isEmpty());
+        assertNull(buffer.poll());
     }
 }