Merge pull request #10917 from amitiw4u/BAEL-4960-StringToBigInt

Bael 4960 string to big int

core-java-modules/core-java-string-conversions-2/src/test/java/com/baeldung/stringtobybiginteger/StringToBigIntegerUnitTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.stringtobybiginteger;
+
+import static org.junit.Assert.assertEquals;
+
+import java.math.BigInteger;
+
+import org.junit.Test;
+
+public class StringToBigIntegerUnitTest {
+
+    @Test
+    public void whenGetStringWithOutRadix_thenOK() {
+        String inputString = "878";
+        BigInteger result = new BigInteger(inputString);
+        assertEquals("878", result.toString());
+    }
+
+    @Test
+    public void whenGetStringWithRadix_thenOK() {
+        String inputString = "290f98";
+        BigInteger result = new BigInteger(inputString, 16);
+        assertEquals("2690968", result.toString());
+    }
+
+    @Test(expected = NumberFormatException.class)
+    public void whenGetStringWithOutRadix_thenThrowError() {
+        String inputString = "290f98";
+        new BigInteger(inputString);
+    }
+
+    @Test(expected = NumberFormatException.class)
+    public void whenGetStringWithRadix_thenThrowError() {
+        String inputString = "290f98";
+        new BigInteger(inputString, 7);
+    }
+
+    @Test
+    public void whenGetStringUsingByte_thenOk() {
+        String inputString = "290f98";
+        byte[] inputStringBytes = inputString.getBytes();
+        BigInteger result = new BigInteger(inputStringBytes);
+        assertEquals("290f98", new String(result.toByteArray()));
+    }
+}