Updated build.gradle to now include some Unit tests

Started implumenting Unit Tests

Core/src/test/java/FileTest.java

@@ -0,0 +1,13 @@
+import me.zacharias.chat.core.files.FileHandler;
+import me.zacharias.chat.core.files.FileHandlerException;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class FileTest {
+    @Test
+    void TestError()
+    {
+        FileHandler fileHandler = new FileHandler("./test/files");
+        Assertions.assertThrowsExactly(FileHandlerException.class, () -> fileHandler.readFile("../build.gradle"));
+    }
+}