Serverless Functions with Spring Cloud Function

/**
 * A Spring Cloud Function implementation that converts a given string to uppercase.
 */
@Component
public class UppercaseFunction implements Function<String, String> {

    /**
     * Input string converted to uppercase.
     */
    @Override
    public String apply(String input) {
        return input.toUpperCase();
    }
}

/**
 * Controller class responsible for handling HTTP requests related to the uppercase conversion function.
 */
@RestController
public class FunctionController {

    /**
     * Endpoint to convert a given string to uppercase.
     */
    @PostMapping("/api/uppercase")
    public String convertToUppercase(@RequestBody String input) {
        return input.toUpperCase();
    }
}

package com.example.serverlessfunctionsdemo;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.MediaType;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.result.MockMvcResultMatchers;

/**
 * This class provides unit tests for the FunctionController class. It ensures that the functionality 
 * of converting a string to uppercase works as expected.
 */
@SpringBootTest
@AutoConfigureMockMvc
public class FunctionControllerTest {

    @Autowired
    private MockMvc mockMvc;

    /**
     * Test case to verify the behavior of converting a string to uppercase in the FunctionController class.
     * @throws Exception if any error occurs during the test execution
     */
    @Test
    public void testConvertToUppercase() throws Exception {
        String input = "hello world";
        String expectedOutput = "HELLO WORLD";

        mockMvc.perform(MockMvcRequestBuilders.post("/api/uppercase")
                        .contentType(MediaType.TEXT_PLAIN)
                        .content(input))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andExpect(MockMvcResultMatchers.content().string(expectedOutput));
    }
}

/**
 * Main class responsible for starting the serverless functions demo application.
 */
@SpringBootApplication
public class ServerlessFunctionsDemoApplication {

    /**
     * Main method to start the application.
     */
    public static void main(String[] args) {
        SpringApplication.run(ServerlessFunctionsDemoApplication.class, args);
    }

}