From 7e66e1b9191c70af81b9b95b21210579e8a5a9ea Mon Sep 17 00:00:00 2001
From: nguyennamthai <namthainguyen@gmail.com>
Date: Mon, 11 Jun 2018 09:44:29 +0700
Subject: [PATCH] BAEL-1801 Add tests for unsigned arithmetic (#4442)

---
 .../java8/UnsignedArithmeticUnitTest.java     | 60 +++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 core-java-8/src/test/java/com/baeldung/java8/UnsignedArithmeticUnitTest.java

diff --git a/core-java-8/src/test/java/com/baeldung/java8/UnsignedArithmeticUnitTest.java b/core-java-8/src/test/java/com/baeldung/java8/UnsignedArithmeticUnitTest.java
new file mode 100644
index 0000000000..e79c90b684
--- /dev/null
+++ b/core-java-8/src/test/java/com/baeldung/java8/UnsignedArithmeticUnitTest.java
@@ -0,0 +1,60 @@
+package com.baeldung.java8;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.catchThrowable;
+import static org.junit.Assert.assertEquals;
+
+public class UnsignedArithmeticUnitTest {
+    @Test
+    public void whenDoublingALargeByteNumber_thenOverflow() {
+        byte b1 = 100;
+        byte b2 = (byte) (b1 << 1);
+
+        assertEquals(-56, b2);
+    }
+
+    @Test
+    public void whenComparingNumbers_thenNegativeIsInterpretedAsUnsigned() {
+        int positive = Integer.MAX_VALUE;
+        int negative = Integer.MIN_VALUE;
+
+        int signedComparison = Integer.compare(positive, negative);
+        assertEquals(1, signedComparison);
+
+        int unsignedComparison = Integer.compareUnsigned(positive, negative);
+        assertEquals(-1, unsignedComparison);
+
+        assertEquals(negative, positive + 1);
+    }
+
+    @Test
+    public void whenDividingNumbers_thenNegativeIsInterpretedAsUnsigned() {
+        int positive = Integer.MAX_VALUE;
+        int negative = Integer.MIN_VALUE;
+
+        assertEquals(-1, negative / positive);
+        assertEquals(1, Integer.divideUnsigned(negative, positive));
+
+        assertEquals(-1, negative % positive);
+        assertEquals(1, Integer.divideUnsigned(negative, positive));
+    }
+
+    @Test
+    public void whenParsingNumbers_thenNegativeIsInterpretedAsUnsigned() {
+        Throwable thrown = catchThrowable(() -> Integer.parseInt("2147483648"));
+        assertThat(thrown).isInstanceOf(NumberFormatException.class);
+
+        assertEquals(Integer.MAX_VALUE + 1, Integer.parseUnsignedInt("2147483648"));
+    }
+
+    @Test
+    public void whenFormattingNumbers_thenNegativeIsInterpretedAsUnsigned() {
+        String signedString = Integer.toString(Integer.MIN_VALUE);
+        assertEquals("-2147483648", signedString);
+
+        String unsignedString = Integer.toUnsignedString(Integer.MIN_VALUE);
+        assertEquals("2147483648", unsignedString);
+    }
+}