Added DispatchersModule.kt and CoroutineTestRule.kt for coroutine dispatchers injection

app/build.gradle

@@ -70,5 +70,6 @@ dependencies {
     implementation "com.jakewharton.timber:timber:$timber_version"
 
     testImplementation "junit:junit:$junit_version"
+    testImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:$coroutines_test_version"
     debugImplementation "com.squareup.leakcanary:leakcanary-android:$leak_canary_version"
 }

app/src/main/java/com/rtbishop/look4sat/di/DispatchersModule.kt

@@ -0,0 +1,57 @@
+/*******************************************************************************
+Look4Sat. Amateur radio satellite tracker and pass predictor.
+Copyright (C) 2019, 2020 Arty Bishop (bishop.arty@gmail.com)
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ ******************************************************************************/
+
+package com.rtbishop.look4sat.di
+
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.Dispatchers
+import javax.inject.Qualifier
+
+@Module
+@InstallIn(SingletonComponent::class)
+object DispatchersModule {
+    
+    @Provides
+    @DefaultDispatcher
+    fun provideDefaultDispatcher(): CoroutineDispatcher = Dispatchers.Default
+    
+    @Provides
+    @IoDispatcher
+    fun provideIoDispatcher(): CoroutineDispatcher = Dispatchers.IO
+    
+    @Provides
+    @MainDispatcher
+    fun provideMainDispatcher(): CoroutineDispatcher = Dispatchers.Main
+}
+
+@Qualifier
+@Retention(AnnotationRetention.BINARY)
+annotation class DefaultDispatcher
+
+@Qualifier
+@Retention(AnnotationRetention.BINARY)
+annotation class IoDispatcher
+
+@Qualifier
+@Retention(AnnotationRetention.BINARY)
+annotation class MainDispatcher

app/src/test/java/com/rtbishop/look4sat/CoroutineTestRule.kt

@@ -0,0 +1,44 @@
+/*******************************************************************************
+Look4Sat. Amateur radio satellite tracker and pass predictor.
+Copyright (C) 2019, 2020 Arty Bishop (bishop.arty@gmail.com)
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ ******************************************************************************/
+
+package com.rtbishop.look4sat
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.TestCoroutineDispatcher
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.setMain
+import org.junit.rules.TestWatcher
+import org.junit.runner.Description
+
+@ExperimentalCoroutinesApi
+class CoroutineTestRule(private val dispatcher: TestCoroutineDispatcher = TestCoroutineDispatcher()) :
+    TestWatcher() {
+    
+    override fun starting(description: Description?) {
+        super.starting(description)
+        Dispatchers.setMain(dispatcher)
+    }
+    
+    override fun finished(description: Description?) {
+        super.finished(description)
+        Dispatchers.resetMain()
+        dispatcher.cleanupTestCoroutines()
+    }
+}

build.gradle

@@ -16,6 +16,7 @@ buildscript {
         timber_version = '4.7.1'
         predict4java_version = '1.3.1'
         junit_version = '4.13.2'
+        coroutines_test_version = '1.3.2'
         leak_canary_version = '2.5'
     }
     repositories {