Fix Resource bugs, add missing tests

Author: Pablo Orgaz

build.gradle

@@ -1,7 +1,7 @@
 buildscript {
     ext {
-        kotlin_version = '1.3.41'
-        mini_version = '4.0.1'
+        kotlin_version = "1.3.41"
+        mini_version = "4.0.2"
     }
 
     repositories {
@@ -11,11 +11,10 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.4.2'
+        classpath "com.android.tools.build:gradle:3.4.2"
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
-        classpath 'org.junit.platform:junit-platform-gradle-plugin:1.0.0'
-        classpath 'com.github.triplet.gradle:play-publisher:1.2.0'
-        classpath 'com.github.dcendents:android-maven-gradle-plugin:2.1'
+        classpath "org.junit.platform:junit-platform-gradle-plugin:1.0.0"
+        classpath "com.github.dcendents:android-maven-gradle-plugin:2.1"
     }
 }
 
@@ -26,7 +25,7 @@ allprojects {
     repositories {
         jcenter()
         mavenCentral()
-        maven { url 'https://jitpack.io' }
+        maven { url "https://jitpack.io" }
         google()
     }
 }

mini-common/src/main/java/mini/Resource.kt

@@ -14,9 +14,15 @@ open class Resource<out T> @PublishedApi internal constructor(val value: Any?) {
     val isFailure: Boolean get() = value is Failure
     val isLoading: Boolean get() = value is Loading<*>
 
-    internal class Empty
-    internal class Failure(val exception: Throwable?)
-    internal class Loading<U>(val value: U? = null)
+    internal class Empty {
+        override fun toString(): String = "Empty()"
+    }
+
+    @PublishedApi
+    internal data class Failure(val exception: Throwable?)
+
+    @PublishedApi
+    internal data class Loading<U>(val value: U? = null)
 
     /**
      * Get the current value if successful, or null for other cases.
@@ -33,12 +39,6 @@ open class Resource<out T> @PublishedApi internal constructor(val value: Any?) {
             else -> null
         }
 
-    override fun toString(): String =
-        when (value) {
-            is Failure -> value.toString() // "Failure($exception)"
-            else -> "Success($value)"
-        }
-
     companion object {
         fun <T> success(value: T): Resource<T> = Resource(value)
         fun <T> failure(exception: Throwable? = null): Resource<T> = Resource(Failure(exception))
@@ -67,23 +67,23 @@ inline fun <T> Resource<T>.onSuccess(crossinline action: (data: T) -> Unit): Res
     return this
 }
 
-inline fun <T> Resource<T>.onFailure(crossinline action: (data: T) -> Unit): Resource<T> {
-    if (isFailure) action(value as T)
+inline fun <T> Resource<T>.onFailure(crossinline action: (error: Throwable?) -> Unit): Resource<T> {
+    if (isFailure) action((value as Resource.Failure).exception)
     return this
 }
 
-inline fun <T> Resource<T>.onLoading(crossinline action: (data: T) -> Unit): Resource<T> {
-    if (isLoading) action(value as T)
+inline fun <T> Resource<T>.onLoading(crossinline action: (data: T?) -> Unit): Resource<T> {
+    if (isLoading) action((value as Resource.Loading<T>).value)
     return this
 }
 
 inline fun Task.onIdle(crossinline action: () -> Unit): Task {
-    onEmpty { action() }
+    if (isEmpty) action()
     return this
 }
 
-inline fun <T> Resource<T>.onEmpty(crossinline action: (data: T) -> Unit): Resource<T> {
-    if (isEmpty) action(value as T)
+inline fun <T> Resource<T>.onEmpty(crossinline action: () -> Unit): Resource<T> {
+    if (isEmpty) action()
     return this
 }
 

mini-common/src/test/kotlin/mini/ResourceTest.kt

@@ -0,0 +1,91 @@
+package mini
+
+import org.amshove.kluent.`should be equal to`
+import org.amshove.kluent.`should be null`
+import org.amshove.kluent.`should equal`
+import org.amshove.kluent.`should not be null`
+import org.junit.Before
+import org.junit.Test
+
+class ResourceTest {
+
+    private var successValue: Any? = null
+    private var errorValue: Any? = null
+    private var loadingValue: Any? = null
+    private var emptyValue: Any? = null
+
+    @Before
+    fun before() {
+        successValue = null
+        errorValue = null
+        loadingValue = null
+        emptyValue = null
+    }
+
+    private fun <T> check(resource: Resource<T>) {
+        var called = 0
+        resource
+            .onSuccess {
+                called++
+                successValue = it
+            }.onFailure {
+                called++
+                errorValue = it
+            }.onLoading {
+                called++
+                loadingValue = it
+            }.onEmpty {
+                called++
+                emptyValue = true
+            }
+        called `should be equal to` 1
+    }
+
+    @Test
+    fun `success calls`() {
+        check(Resource.success("abc"))
+        successValue `should equal` "abc"
+    }
+
+    @Test
+    fun isEmpty() {
+        check(Resource.empty<Any>())
+        emptyValue `should equal` true
+    }
+
+    @Test
+    fun isFailure() {
+        val ex = RuntimeException("ABC")
+        check(Resource.failure<Any>(ex))
+        errorValue `should equal` ex
+    }
+
+    @Test
+    fun isLoading() {
+        check(Resource.loading<Any>("abc"))
+        loadingValue `should equal` "abc"
+    }
+
+    @Test
+    fun getOrNull() {
+        Resource.empty<Any>().getOrNull().`should be null`()
+        Resource.success("abc").getOrNull().`should not be null`()
+    }
+
+    @Test
+    fun exceptionOrNull() {
+        Resource.failure<Any>(RuntimeException()).exceptionOrNull().`should not be null`()
+        Resource.success<Any>("abc").exceptionOrNull(). `should be null` ()
+    }
+
+    @Test
+    fun map() {
+        Resource.success("abc")
+            .map { 0 }
+            .getOrNull()?.`should be equal to`(0)
+
+        Resource.failure<Any>()
+            .map { 0 }
+            .getOrNull()?.`should be null`()
+    }
+}