Add test case for BinaryToHexadecimal (#3694)

src/test/java/com/thealgorithms/conversions/BinaryToHexadecimalTest.java

@@ -0,0 +1,14 @@
+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class BinaryToHexadecimalTest {
+
+    @Test
+    public void testBinaryToHexadecimal() {
+        assertEquals("6A", BinaryToHexadecimal.binToHex(1101010));
+        assertEquals("C", BinaryToHexadecimal.binToHex(1100));
+    }
+}