From 25efd807d1817a6404c8c98f65ad82b7b6d9d192 Mon Sep 17 00:00:00 2001
From: Mohammad <mmohammadq8@outlook.com>
Date: Thu, 26 Jun 2025 10:41:47 +0300
Subject: [PATCH] Add tests for empty product response and enhance product
 fetching logic

---
 pom.xml                                       | 19 +++++++
 .../copilotdemo/services/ProductsService.kt   | 53 +++++++++++++++++++
 .../controllers/ProductsControllerTest.kt     | 13 +++++
 3 files changed, 85 insertions(+)

diff --git a/pom.xml b/pom.xml
index b98eaac..cb6ca19 100644
--- a/pom.xml
+++ b/pom.xml
@@ -47,6 +47,25 @@
             <groupId>org.jetbrains.kotlin</groupId>
             <artifactId>kotlin-stdlib</artifactId>
         </dependency>
+        <!-- https://mvnrepository.com/artifact/io.cucumber/cucumber-spring -->
+        <dependency>
+            <groupId>io.cucumber</groupId>
+            <artifactId>cucumber-spring</artifactId>
+            <version>7.23.0</version>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/io.cucumber/cucumber-junit-platform-engine -->
+        <dependency>
+            <groupId>io.cucumber</groupId>
+            <artifactId>cucumber-junit-platform-engine</artifactId>
+            <version>7.23.0</version>
+            <scope>test</scope>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/io.cucumber/cucumber-java -->
+        <dependency>
+            <groupId>io.cucumber</groupId>
+            <artifactId>cucumber-java</artifactId>
+            <version>7.23.0</version>
+        </dependency>
 
         <dependency>
             <groupId>org.springframework.boot</groupId>
diff --git a/src/main/kotlin/com/example/copilotdemo/services/ProductsService.kt b/src/main/kotlin/com/example/copilotdemo/services/ProductsService.kt
index 537c2f5..f8c1f34 100644
--- a/src/main/kotlin/com/example/copilotdemo/services/ProductsService.kt
+++ b/src/main/kotlin/com/example/copilotdemo/services/ProductsService.kt
@@ -30,6 +30,14 @@ class ProductsService {
         val total: Int
     )
 
+
+    /**
+     * Retrieves a paginated list of products and the total count from the external DummyJSON API.
+     *
+     * @param start The starting index (number of products to skip).
+     * @param size The number of products to retrieve.
+     * @return [ProductsResult] containing the list of products and the total count.
+     */
     fun getProductsAndTotal(start: Int, size: Int): ProductsResult {
         if (start < 0 || size < 1) return ProductsResult(emptyList(), 0)
         val url = UriComponentsBuilder.fromUriString(baseUrl)
@@ -37,6 +45,7 @@ class ProductsService {
             .queryParam("limit", size)
             .toUriString()
         val response = restTemplate.getForObject(url, DummyJsonResponse::class.java)
+
         val products = response?.products?.map {
             Product(
                 id = it.id.toLong(),
@@ -50,4 +59,48 @@ class ProductsService {
         val total = response?.total ?: 0
         return ProductsResult(products, total)
     }
+
+    /**
+     * Fetches all products from the external API in batches of 20.
+     * @return ProductsResult containing all products and the total count.
+     */
+    fun getAllProductsInBatches(): ProductsResult {
+        val batchSize = 20
+        val firstBatch = getProductsAndTotal(0, batchSize)
+        val total = firstBatch.total
+        val allProducts = mutableListOf<Product>()
+        allProducts.addAll(firstBatch.products)
+        var fetched = firstBatch.products.size
+        while (fetched < total) {
+            val batch = getProductsAndTotal(fetched, batchSize)
+            allProducts.addAll(batch.products)
+            fetched += batch.products.size
+            if (batch.products.isEmpty()) break // safety check
+        }
+        return ProductsResult(allProducts, total)
+    }
+
+
+
 }
+
+
+
+
+
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+
diff --git a/src/test/kotlin/com/example/copilotdemo/controllers/ProductsControllerTest.kt b/src/test/kotlin/com/example/copilotdemo/controllers/ProductsControllerTest.kt
index 164c22a..c99a2bc 100644
--- a/src/test/kotlin/com/example/copilotdemo/controllers/ProductsControllerTest.kt
+++ b/src/test/kotlin/com/example/copilotdemo/controllers/ProductsControllerTest.kt
@@ -16,6 +16,7 @@ import org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPat
 import org.springframework.test.web.servlet.result.MockMvcResultMatchers.status
 import org.springframework.web.client.RestTemplate
 
+@Suppress("SpringJavaInjectionPointsAutowiringInspection")
 @SpringBootTest
 @AutoConfigureMockMvc
 class ProductsControllerTest {
@@ -56,6 +57,18 @@ class ProductsControllerTest {
             .andReturn()
     }
 
+    // write a test case to handle empty response from the service
+    @Test
+    fun `should return empty products when service returns no products`() {
+        val dummyResponse = ProductsService.DummyJsonResponse(products = emptyList(), total = 0)
+        Mockito.`when`(
+            restTemplate.getForObject(Mockito.anyString(), Mockito.eq(ProductsService.DummyJsonResponse::class.java))
+        ).thenReturn(dummyResponse)
 
+        mockMvc.perform(get("/api/v1/products?start=0&size=10").accept(MediaType.APPLICATION_JSON))
+            .andExpect(status().isOk)
+            .andExpect(jsonPath("$.products").isEmpty)
+            .andExpect(jsonPath("$.total").value(0))
+    }
 }