From 59c5979c0a27e7926e323a80d75f1ec7b6968e76 Mon Sep 17 00:00:00 2001
From: Adetunji Dahunsi <dahunsi@google.com>
Date: Wed, 4 May 2022 12:40:13 -0400
Subject: [PATCH] Catch exceptions in the flow.asResult method

Change-Id: I0289e535b8811be95b58b2ea4abe515ab4191cfc
---
 core-common/build.gradle.kts                  |  2 +
 .../apps/nowinandroid/core/result/Result.kt   |  2 +
 .../nowinandroid/core/result/ResultKtTest.kt  | 52 +++++++++++++++++++
 3 files changed, 56 insertions(+)
 create mode 100644 core-common/src/test/java/com/google/samples/apps/nowinandroid/core/result/ResultKtTest.kt

diff --git a/core-common/build.gradle.kts b/core-common/build.gradle.kts
index 33464929a..a04464ef0 100644
--- a/core-common/build.gradle.kts
+++ b/core-common/build.gradle.kts
@@ -24,4 +24,6 @@ dependencies {
     implementation(libs.kotlinx.coroutines.android)
     implementation(libs.hilt.android)
     kapt(libs.hilt.compiler)
+
+    testImplementation(project(":core-testing"))
 }
\ No newline at end of file
diff --git a/core-common/src/main/java/com/google/samples/apps/nowinandroid/core/result/Result.kt b/core-common/src/main/java/com/google/samples/apps/nowinandroid/core/result/Result.kt
index d53d544bb..4a06b8b9d 100644
--- a/core-common/src/main/java/com/google/samples/apps/nowinandroid/core/result/Result.kt
+++ b/core-common/src/main/java/com/google/samples/apps/nowinandroid/core/result/Result.kt
@@ -17,6 +17,7 @@
 package com.google.samples.apps.nowinandroid.core.result
 
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onStart
 
@@ -32,4 +33,5 @@ fun <T> Flow<T>.asResult(): Flow<Result<T>> {
             Result.Success(it)
         }
         .onStart { emit(Result.Loading) }
+        .catch { emit(Result.Error(it)) }
 }
diff --git a/core-common/src/test/java/com/google/samples/apps/nowinandroid/core/result/ResultKtTest.kt b/core-common/src/test/java/com/google/samples/apps/nowinandroid/core/result/ResultKtTest.kt
new file mode 100644
index 000000000..964ac2ab5
--- /dev/null
+++ b/core-common/src/test/java/com/google/samples/apps/nowinandroid/core/result/ResultKtTest.kt
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.samples.apps.nowinandroid.core.result
+
+import app.cash.turbine.test
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.test.runTest
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class ResultKtTest {
+
+    @Test
+    fun Result_catches_errors() = runTest {
+        flow {
+            emit(1)
+            throw Exception("Test Done")
+        }
+            .asResult()
+            .test {
+                assertEquals(Result.Loading, awaitItem())
+                assertEquals(Result.Success(1), awaitItem())
+
+                when (val errorResult = awaitItem()) {
+                    is Result.Error -> assertEquals(
+                        "Test Done",
+                        errorResult.exception?.message
+                    )
+                    Result.Loading,
+                    is Result.Success -> throw IllegalStateException(
+                        "The flow should have emitted an Error Result"
+                    )
+                }
+
+                awaitComplete()
+            }
+    }
+}