add tests for GreetingController

src/test/kotlin/com/example/demo/controllers/GreetingControllerTest.kt

@@ -0,0 +1,30 @@
+package com.example.demo.controllers
+
+import org.hamcrest.core.StringContains
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest
+import org.springframework.test.web.servlet.MockMvc
+import org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get
+import org.springframework.test.web.servlet.result.MockMvcResultMatchers.content
+import org.springframework.test.web.servlet.result.MockMvcResultMatchers.status
+import kotlin.test.Test
+
+@WebMvcTest(GreetingController::class)
+class GreetingControllerTest(@Autowired val mockMvc: MockMvc) {
+
+    @Test
+    fun greetings_shouldSeeGreetingMessage() {
+        mockMvc.perform(get("/greeting"))
+            .andExpect(status().isOk)
+            .andExpect(content().contentType("text/plain;charset=UTF-8"))
+            .andExpect(content().string("Hello World!"))
+    }
+
+    @Test
+    fun exampleHtml_shouldSeeRenderedHtml() {
+        mockMvc.perform(get("/example/html"))
+            .andExpect(status().isOk)
+            .andExpect(content().contentType("text/html;charset=UTF-8"))
+            .andExpect(content().string(StringContains("Product")))
+    }
+}