Merge pull request #225 from myofficework000/mockk_and_mock_testcases

headline news api repository test cases with mockk

app/src/test/java/com/example/jetpack_compose_all_in_one/features/newsapi/NewsAPIRepositoryMockkTest.kt

@@ -0,0 +1,90 @@
+package com.example.jetpack_compose_all_in_one.features.newsapi
+
+import com.example.jetpack_compose_all_in_one.features.newsapi.data.data.Article
+import com.example.jetpack_compose_all_in_one.features.newsapi.data.data.HeadlineResponse
+import com.example.jetpack_compose_all_in_one.features.newsapi.data.data.Source
+import com.example.jetpack_compose_all_in_one.features.newsapi.data.remote.NewsApiService
+import com.example.jetpack_compose_all_in_one.features.newsapi.repository.NewsApiRepositoryImpl
+import com.example.jetpack_compose_all_in_one.utils.Constants
+import com.example.jetpack_compose_all_in_one.utils.ResultState
+import io.mockk.coEvery
+import io.mockk.mockk
+import kotlinx.coroutines.test.runTest
+import okhttp3.MediaType.Companion.toMediaTypeOrNull
+import okhttp3.ResponseBody.Companion.toResponseBody
+import org.junit.Before
+import org.junit.Test
+import retrofit2.Response
+
+class NewsAPIRepositoryMockkTest {
+    private val apiService = mockk<NewsApiService>(relaxed = true)
+    lateinit var newsApiRepositoryImpl: NewsApiRepositoryImpl
+
+    @Before
+    fun setup(){
+        newsApiRepositoryImpl = NewsApiRepositoryImpl(apiService)
+    }
+
+    @Test
+    fun `Given news data is empty, When fetching news data, Then returns empty list `() = runTest {
+        coEvery { apiService.getTopHeadlines(Constants.NEWS_API_COUNTRY, Constants.NEWS_API_KEY) } returns Response.success(
+            HeadlineResponse(listOf(),"0",0)
+        )
+       val result = newsApiRepositoryImpl.getHeadLines()
+
+        result.collect{
+            if(it is ResultState.Success){
+               assert(it.body?.status == "0")
+               assert(it.body?.totalResults == 0)
+               assert(it.body?.articles == emptyList<Article>())
+            }
+        }
+    }
+
+    @Test
+    fun `Given news data is NOT empty, When fetching news data, Then returns NOT empty list `() = runTest {
+        coEvery { apiService.getTopHeadlines(Constants.NEWS_API_COUNTRY, Constants.NEWS_API_KEY) } returns Response.success(
+            HeadlineResponse(listOfArticle,"200",1)
+        )
+        val result = newsApiRepositoryImpl.getHeadLines()
+
+        result.collect{
+            if(it is ResultState.Success){
+                assert(it.body?.status == "200")
+                assert(it.body?.totalResults == 1)
+                assert(it.body?.articles?.size == 1)
+            }
+        }
+    }
+
+    @Test
+    fun `Given news data is empty, When fetching news data, Then returns error `() = runTest {
+        val errorResponse = "Error!"
+        val errorResponseBody = errorResponse.toResponseBody("application/json".toMediaTypeOrNull())
+        val mockResponse = Response.error<HeadlineResponse>(400, errorResponseBody)
+        coEvery {
+            apiService.getTopHeadlines(
+                Constants.NEWS_API_COUNTRY,
+                Constants.NEWS_API_KEY
+            )
+        } returns mockResponse
+
+        val result = newsApiRepositoryImpl.getHeadLines()
+
+        result.collect {
+            assert(it is ResultState.Error)
+            if (it is ResultState.Error) {
+                assert(it.errorMessage == "Error: 400")
+            }
+        }
+    }
+
+    companion object {
+        val listOfArticle = listOf(
+            Article(
+                author = "A", content = "A", description = "A", publishedAt = "A",
+                source = Source(id = "A", name = "A"), title = "A", url = "", urlToImage = ""
+            )
+        )
+    }
+}