Convert leakcanary-sample to Kotlin (#1229)

See #1205

leakcanary-sample/build.gradle

@@ -3,7 +3,7 @@ apply plugin: 'kotlin-android'
 
 dependencies {
   implementation deps.kotlin.stdLib.jdk8
-  debugImplementation project(':leakcanary-android')
+  implementation project(':leakcanary-android')
 
   testImplementation "junit:junit:4.12"
   testImplementation "org.robolectric:robolectric:4.0-alpha-3"

leakcanary-sample/src/androidTest/java/com/example/leakcanary/tests/InstrumentationExampleApplication.kt

@@ -0,0 +1,12 @@
+package com.example.leakcanary.tests
+
+import com.example.leakcanary.ExampleApplication
+import com.squareup.leakcanary.InstrumentationLeakDetector
+
+class InstrumentationExampleApplication : ExampleApplication() {
+
+  override fun setupLeakCanary() {
+    InstrumentationLeakDetector.instrumentationRefWatcher(this)
+        .buildAndInstall()
+  }
+}

leakcanary-sample/src/androidTest/java/com/example/leakcanary/tests/TuPeuxPasTest.kt

@@ -0,0 +1,52 @@
+package com.example.leakcanary.tests
+
+import androidx.test.rule.ActivityTestRule
+import com.example.leakcanary.MainActivity
+import com.example.leakcanary.R
+import org.junit.Rule
+import org.junit.Test
+
+import androidx.test.espresso.Espresso.onView
+import androidx.test.espresso.action.ViewActions.click
+import androidx.test.espresso.assertion.ViewAssertions.matches
+import androidx.test.espresso.matcher.ViewMatchers.withId
+import androidx.test.espresso.matcher.ViewMatchers.withText
+
+/**
+ * This UI test looks like it should succeed, but it will actually fail because
+ * it triggers a leak.
+ *
+ * Run this test with:
+ *
+ * ./gradlew leakcanary-sample:connectedCheck
+ *
+ * To set this up, we installed a special RefWatcher dedicated to detecting leaks in
+ * instrumentation tests in [InstrumentationExampleApplication], and then added the FailTestOnLeakRunListener
+ * to the config of our build.gradle:
+ *
+ * testInstrumentationRunnerArgument "listener", "com.squareup.leakcanary.FailTestOnLeakRunListener"
+ *
+ *
+ * Why is this class named "TuPeuxPasTest"?
+ *
+ * This test fails, intentionally. In French, "Tu peux pas test" could mean "you cannot test"
+ * written with poor grammar. Except, that's not what it means.
+ * If you're curious, interested in French and have time to waste:
+ * https://www.youtube.com/watch?v=DZZpbmAc-0A
+ * https://www.youtube.com/watch?v=nHeAA6X-XUQ
+ */
+class TuPeuxPasTest {
+
+  @Rule
+  var activityRule = ActivityTestRule(MainActivity::class.java)
+
+  @Test
+  fun clickAsyncWork() {
+    onView(withId(R.id.async_work)).perform(click())
+  }
+
+  @Test
+  fun asyncButtonHasStartText() {
+    onView(withId(R.id.async_work)).check(matches(withText(R.string.start_async_work)))
+  }
+}

leakcanary-sample/src/main/java/com/example/leakcanary/ExampleApplication.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2015 Square, Inc.
+ *
+ * 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
+ *
+ *      http://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.example.leakcanary
+
+import android.app.Application
+import android.os.Build
+import android.os.StrictMode
+import com.squareup.leakcanary.LeakCanary
+
+open class ExampleApplication : Application() {
+  override fun onCreate() {
+    super.onCreate()
+    setupLeakCanary()
+  }
+
+  protected open fun setupLeakCanary() {
+    enabledStrictMode()
+    if (LeakCanary.isInAnalyzerProcess(this)) {
+      // This process is dedicated to LeakCanary for heap analysis.
+      // You should not init your app in this process.
+      return
+    }
+    LeakCanary.install(this)
+  }
+
+  companion object {
+    private fun enabledStrictMode() {
+      val builder = StrictMode.ThreadPolicy.Builder()
+      // Disabled DiskReadViolation, see https://github.com/square/leakcanary/issues/1222
+      //    builder.detectDiskReads();
+      builder.detectDiskWrites()
+      builder.detectNetwork()
+      builder.detectCustomSlowCalls()
+      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+        builder.detectResourceMismatches()
+      }
+      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+        builder.detectUnbufferedIo()
+      }
+      builder.penaltyLog()
+      builder.penaltyDeath()
+      StrictMode.setThreadPolicy(builder.build())
+    }
+  }
+}

leakcanary-sample/src/main/java/com/example/leakcanary/HttpRequestHelper.java → leakcanary-sample/src/main/java/com/example/leakcanary/HttpRequestHelper.kt

@@ -13,18 +13,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.example.leakcanary;
+package com.example.leakcanary
 
-import android.view.View;
+import android.view.View
 
 /**
  * Fake class for the purpose of demonstrating a leak.
  */
-public class HttpRequestHelper {
-
-  private final View button;
-
-  HttpRequestHelper(View button) {
-    this.button = button;
-  }
-}
+class HttpRequestHelper internal constructor(private val button: View)

leakcanary-sample/src/test/java/com/example/leakcanary/SampleTest.kt

@@ -0,0 +1,20 @@
+package com.example.leakcanary
+
+import android.view.View
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.Robolectric
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+@RunWith(RobolectricTestRunner::class)
+@Config(application = TestExampleApplication::class)
+class SampleTest {
+  @Test
+  fun testTheThing() {
+    val controller = Robolectric.buildActivity(MainActivity::class.java).create().start().resume().visible()
+    controller.get().findViewById<View>(R.id.async_work).performClick()
+    controller.stop()
+    controller.destroy()
+  }
+}

leakcanary-sample/src/test/java/com/example/leakcanary/TestExampleApplication.kt

@@ -0,0 +1,7 @@
+package com.example.leakcanary
+
+class TestExampleApplication : ExampleApplication() {
+  override fun setupLeakCanary() {
+    // No leakcanary in unit tests.
+  }
+}