Restore test file

src/test/java/com/example/demo/DemoApplicationTests.java

+package com.example.demo;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.junit4.SpringRunner;
+import static org.assertj.core.api.Assertions.assertThat;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
+public class DemoApplicationTests {
+
+	@Test
+	public void contextLoads() {
+	}
+
+	@Autowired
+	private TestRestTemplate restTemplate;
+
+	@Test
+	public void homeResponse() {
+		String body = this.restTemplate.getForObject("/", String.class);
+		assertThat(body).isEqualTo("Spring is here!");
+	}
+}