diff --git a/src/language/typescript/common/bundled/__tests__/client.spec.ts b/src/language/typescript/common/bundled/__tests__/client.spec.ts
new file mode 100644
index 0000000..071a8d8
--- /dev/null
+++ b/src/language/typescript/common/bundled/__tests__/client.spec.ts
@@ -0,0 +1,33 @@
+import * as typescript from 'typescript';
+import { client } from '../client';
+
+describe('client', () => {
+	describe('ResponseValidationError class', () => {
+		it('should produce uniquely identifiable instance of itself', () => {
+			const exports = {} as any;
+
+			const clientCodeTranspiled = typescript.transpile(client, {
+				target: typescript.ScriptTarget.ESNext,
+				module: typescript.ModuleKind.None,
+			});
+
+			// eslint-disable-next-line no-eval
+			eval(clientCodeTranspiled);
+
+			expect(exports.ResponseValidationError.create([])).toBeInstanceOf(exports.ResponseValidationError);
+			expect(exports.ResponseValidationError.create([])).toBeInstanceOf(Error);
+		});
+		it('should produce instance that not crashing when its casted to string', () => {
+			const exports = {} as any;
+			const clientCodeTranspiled = typescript.transpile(client, {
+				target: typescript.ScriptTarget.ESNext,
+				module: typescript.ModuleKind.None,
+			});
+
+			// eslint-disable-next-line no-eval
+			eval(clientCodeTranspiled);
+
+			expect(() => String(exports.ResponseValidationError.create([]))).not.toThrow();
+		});
+	});
+});
diff --git a/src/language/typescript/common/bundled/client.ts b/src/language/typescript/common/bundled/client.ts
index 6815cdb..9645b29 100644
--- a/src/language/typescript/common/bundled/client.ts
+++ b/src/language/typescript/common/bundled/client.ts
@@ -6,20 +6,20 @@ import { pipe } from 'fp-ts/lib/pipeable';
 export const clientRef = fromString('#/client/client');
 
 //TODO: make WebSocketChannelRequest.query a string after https://github.com/asyncapi/asyncapi/issues/294
-const client = `
+export const client = `
 	import { HKT, Kind, Kind2, URIS, URIS2 } from 'fp-ts/lib/HKT';
 	import { MonadThrow, MonadThrow1, MonadThrow2 } from 'fp-ts/lib/MonadThrow';
 	import { Errors } from 'io-ts';
 	import { PathReporter } from 'io-ts/lib/PathReporter';
 	import { left } from 'fp-ts/lib/Either';
-	
+
 	export interface Request {
 		readonly method: 'GET' | 'POST' | 'PUT' | 'DELETE' | 'PATCH' | 'HEAD' | 'OPTIONS';
 		readonly url: string;
 		readonly query?: string;
 		readonly body?: unknown;
 	}
-	
+
 	export interface HTTPClient<F> extends MonadThrow<F> {
 		readonly request: (request: Request) => HKT<F, unknown>;
 	}
@@ -29,14 +29,14 @@ const client = `
 	export interface HTTPClient2<F extends URIS2> extends MonadThrow2<F> {
 		readonly request: (request: Request) => Kind2<F, unknown, unknown>;
 	}
-	
+
 	export interface WebSocketChannelRequest {
 		readonly method: 'GET' | 'POST';
 		readonly channel: string;
 		readonly query?: Record<string, unknown>;
 		readonly headers?: Record<string, unknown>;
 	}
-	
+
 	export interface WebSocketClient2<F extends URIS2> {
 		readonly channel: (request: WebSocketChannelRequest) => WebSocketChannel2<F>;
 	}
@@ -46,7 +46,7 @@ const client = `
 	export interface WebSocketClient<F> {
 		readonly channel: (request: WebSocketChannelRequest) => WebSocketChannel<F>;
 	}
-	
+
 	export interface WebSocketChannel<F> extends MonadThrow<F> {
 		readonly send: (payload: unknown) => void;
 		readonly message: HKT<F, unknown>
@@ -59,16 +59,16 @@ const client = `
 		readonly send: (payload: unknown) => void;
 		readonly message: Kind2<F, unknown, unknown>
 	}
-	
+
 	export class ResponseValidationError extends Error {
 		static create(errors: Errors): ResponseValidationError {
 			return new ResponseValidationError(errors);
 		}
-	
+
 		constructor(readonly errors: Errors) {
 			super(PathReporter.report(left(errors)).join('\\n\\n'));
 			this.name = 'ResponseValidationError';
-			Object.setPrototypeOf(this, ResponseValidationError);
+			Object.setPrototypeOf(this, ResponseValidationError.prototype);
 		}
 	}
 `;