<dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.2.7.RELEASE</version>
        </dependency>    

String filePaht = "";
File imageFile = new File(filePath);
FileInputStream in = new FileInputStream(imageFile);
MultipartFile file = new MockMultipartFile("file", imageFile.getName(), "text/plain", IOUtils.toByteArray(in));