Add BcdConversion algorithm (#5742)

src/test/java/com/thealgorithms/bitmanipulation/BcdConversionTest.java

@@ -0,0 +1,65 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the BcdConversion class.
+ */
+public class BcdConversionTest {
+
+    /**
+     * Test the bcdToBinary method with a BCD number.
+     */
+    @Test
+    public void testBcdToBinary() {
+        int binary = BcdConversion.bcdToBinary(0x1234);
+        assertEquals(1234, binary); // BCD 0x1234 should convert to binary 1234
+    }
+
+    /**
+     * Test the binaryToBcd method with a binary number.
+     */
+    @Test
+    public void testBinaryToBcd() {
+        int bcd = BcdConversion.binaryToBcd(1234);
+        assertEquals(0x1234, bcd); // Binary 1234 should convert to BCD 0x1234
+    }
+
+    /**
+     * Test the bcdToBinary method with zero.
+     */
+    @Test
+    public void testBcdToBinaryZero() {
+        int binary = BcdConversion.bcdToBinary(0x0);
+        assertEquals(0, binary); // BCD 0x0 should convert to binary 0
+    }
+
+    /**
+     * Test the binaryToBcd method with zero.
+     */
+    @Test
+    public void testBinaryToBcdZero() {
+        int bcd = BcdConversion.binaryToBcd(0);
+        assertEquals(0x0, bcd); // Binary 0 should convert to BCD 0x0
+    }
+
+    /**
+     * Test the bcdToBinary method with a single digit BCD number.
+     */
+    @Test
+    public void testBcdToBinarySingleDigit() {
+        int binary = BcdConversion.bcdToBinary(0x7);
+        assertEquals(7, binary); // BCD 0x7 should convert to binary 7
+    }
+
+    /**
+     * Test the binaryToBcd method with a single digit binary number.
+     */
+    @Test
+    public void testBinaryToBcdSingleDigit() {
+        int bcd = BcdConversion.binaryToBcd(7);
+        assertEquals(0x7, bcd); // Binary 7 should convert to BCD 0x7
+    }
+}