spring-test-slices: Spring Boot 4.1.2 test slices lab (@WebMvcTest, @JsonTest, @RestClientTest, @DataJpaTest vs @SpringBootTest)

Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b7Jbw5CxUQ13D7gn25
2026-11-14 15:26:55 +05:30
parent c92977b23d
commit d7497c8ab1
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+package lab.slices;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import java.math.BigDecimal;
+import java.time.LocalDate;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.webmvc.test.autoconfigure.WebMvcTest;
+import org.springframework.context.ApplicationContext;
+import org.springframework.test.context.bean.override.mockito.MockitoBean;
+import org.springframework.test.web.servlet.MockMvc;
+
+/** @WebMvcTest: the web layer only. BookService is replaced by a Mockito mock. */
+@WebMvcTest(BookController.class)
+class WebMvcSliceTest {
+
+    @Autowired
+    MockMvc mvc;
+
+    @Autowired
+    ApplicationContext ctx;
+
+    @MockitoBean
+    BookService service;
+
+    @Test
+    void returnsABookAsJson_usingTheJacksonComponentAndTheControllerAdvice() throws Exception {
+        given(service.get(1L)).willReturn(
+                new Book("9780134685991", "Effective Java", "Joshua Bloch", new BigDecimal("499"), LocalDate.of(2018, 1, 6)));
+        given(service.get(99L)).willThrow(new BookNotFoundException(99L));
+
+        String ok = mvc.perform(get("/api/books/1"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$.title").value("Effective Java"))
+                .andExpect(jsonPath("$.price").value("INR 499.00"))
+                .andExpect(jsonPath("$.published_on").value("2018-01-06"))
+                .andReturn().getResponse().getContentAsString();
+
+        String missing = mvc.perform(get("/api/books/99"))
+                .andExpect(status().isNotFound())
+                .andExpect(jsonPath("$.title").value("Book not found"))
+                .andReturn().getResponse().getContentAsString();
+
+        Transcript t = new Transcript("01-webmvc-slice.txt")
+                .line("@WebMvcTest(BookController.class) with @MockitoBean BookService")
+                .line("")
+                .line("GET /api/books/1   -> 200 %s", ok)
+                .line("GET /api/books/99  -> 404 %s", missing)
+                .line("")
+                .line("beans in this context:");
+        BeanProbe.record("WebMvcTest", ctx).forEach(l -> t.line("  %s", l));
+        t.write();
+
+        assertThat(ctx.getBeanNamesForType(BookService.class)).as("the mock is the only BookService").hasSize(1);
+        assertThat(ctx.getBeanNamesForType(BookRepository.class)).isEmpty();
+        assertThat(ctx.getBeanNamesForType(AuditLogger.class)).isEmpty();
+    }
+}