[BAEL-1967] - Custom validation MessageSource in Spring Boot

spring-boot-mvc/src/test/java/com/baeldung/springbootmvc/LoginControllerUnitTest.java

@@ -0,0 +1,35 @@
+package com.baeldung.springbootmvc;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.MvcResult;
+import org.springframework.test.web.servlet.RequestBuilder;
+import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
+
+import com.baeldung.springbootmvc.config.CustomMessageSourceConfiguration;
+
+@RunWith(SpringRunner.class)
+@WebMvcTest(value = LoginController.class, secure = false)
+@ContextConfiguration(classes = { SpringBootMvcApplication.class, CustomMessageSourceConfiguration.class })
+public class LoginControllerUnitTest {
+
+    @Autowired
+    private MockMvc mockMvc;
+
+    @Test
+    public void givenLoginForm_whenEmailFieldNotProvided_testCustomValidMessageIsReturned() throws Exception {
+
+        RequestBuilder builder = MockMvcRequestBuilders.post("/loginform").param("email", "").param("password", "helo");
+
+        // header("accept-language", "fr").
+        MvcResult perform = mockMvc.perform(builder).andReturn();
+        Assert.assertTrue(perform.getResolvedException().getMessage().contains("valid email"));
+
+    }
+}