fix: Rename UnsupportedHttpError into BadRequestError.

test/unit/util/errors/BadRequestHttpError.test.ts

@@ -0,0 +1,17 @@
+import { BadRequestHttpError } from '../../../../src/util/errors/BadRequestHttpError';
+
+describe('An BadRequestHttpError', (): void => {
+  it('has status code 400.', async(): Promise<void> => {
+    const error = new BadRequestHttpError('test');
+
+    expect(error.statusCode).toEqual(400);
+    expect(error.message).toEqual('test');
+    expect(error.name).toEqual('BadRequestHttpError');
+  });
+
+  it('has a default message if none was provided.', async(): Promise<void> => {
+    const error = new BadRequestHttpError();
+
+    expect(error.message).toEqual('The given input is not supported by the server configuration.');
+  });
+});