Add Android smoke test for incremental Java compilation

subprojects/smoke-test/smoke-test.gradle.kts

@@ -55,6 +55,9 @@ dependencies {
     smokeTestImplementation(project(":persistentCache"))
     smokeTestImplementation(library("commons_io"))
     smokeTestImplementation(library("jgit"))
+    smokeTestImplementation(library("gradleProfiler")) {
+        because("Using build mutators to change a Java file")
+    }
     smokeTestImplementation(testLibrary("spock"))
 
     val allTestRuntimeDependencies: DependencySet by rootProject.extra

subprojects/smoke-test/src/smokeTest/groovy/org/gradle/smoketests/AndroidPluginsSmokeTest.groovy

@@ -123,6 +123,12 @@ class AndroidPluginsSmokeTest extends AbstractSmokeTest {
             </manifest>""".stripIndent()
 
         writeActivity(app, appPackage, appActivity)
+        file("${app}/src/main/java/UsesLibraryActivity.java") << """
+            public class UsesLibraryActivity {
+                public void consume(${libPackage}.${libraryActivity} activity) {
+                }
+            }
+        """
         file("${app}/src/main/AndroidManifest.xml") << """<?xml version="1.0" encoding="utf-8"?>
             <manifest xmlns:android="http://schemas.android.com/apk/res/android"
                 package="${appPackage}">
@@ -192,6 +198,14 @@ class AndroidPluginsSmokeTest extends AbstractSmokeTest {
             expectNoDeprecationWarnings(result)
         }
 
+        when: 'abi change on library'
+        writeActivity(library, libPackage, libraryActivity, true)
+        result = runner('build', '-x', 'lint').build()
+
+        then: 'dependent sources are recompiled'
+        result.task(':library:compileReleaseJavaWithJavac').outcome == TaskOutcome.SUCCESS
+        result.task(':app:compileReleaseJavaWithJavac').outcome == TaskOutcome.SUCCESS
+
         where:
         pluginVersion << TestedVersions.androidGradle
     }
@@ -219,10 +233,10 @@ class AndroidPluginsSmokeTest extends AbstractSmokeTest {
         """.stripIndent()
     }
 
-    private writeActivity(String basedir, String packageName, String className) {
+    private writeActivity(String basedir, String packageName, String className, changed = false) {
         String resourceName = className.toLowerCase()
 
-        file("${basedir}/src/main/java/${packageName.replaceAll('\\.', '/')}/HelloActivity.java") << """
+        file("${basedir}/src/main/java/${packageName.replaceAll('\\.', '/')}/${className}.java").text = """
             package ${packageName};
 
             import org.joda.time.LocalTime;
@@ -231,7 +245,7 @@ class AndroidPluginsSmokeTest extends AbstractSmokeTest {
             import android.os.Bundle;
             import android.widget.TextView;
 
-            public class HelloActivity extends Activity {
+            public class ${className} extends Activity {
 
                 @Override
                 public void onCreate(Bundle savedInstanceState) {
@@ -247,9 +261,10 @@ class AndroidPluginsSmokeTest extends AbstractSmokeTest {
                     textView.setText("The current local time is: " + currentTime);
                 }
 
+                ${changed ? "public void doStuff() {}" : ""}
             }""".stripIndent()
 
-        file("${basedir}/src/main/res/layout/${resourceName}_layout.xml") << '''<?xml version="1.0" encoding="utf-8"?>
+        file("${basedir}/src/main/res/layout/${resourceName}_layout.xml").text =  '''<?xml version="1.0" encoding="utf-8"?>
             <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                 android:orientation="vertical"
                 android:layout_width="fill_parent"

subprojects/smoke-test/src/smokeTest/groovy/org/gradle/smoketests/AndroidSantaTrackerSmokeTest.groovy

@@ -18,6 +18,7 @@ package org.gradle.smoketests
 
 import org.gradle.integtests.fixtures.daemon.DaemonLogsAnalyzer
 import org.gradle.internal.scan.config.fixtures.GradleEnterprisePluginSettingsFixture
+import org.gradle.profiler.mutations.ApplyNonAbiChangeToJavaSourceFileMutator
 import org.gradle.test.fixtures.file.TestFile
 import org.gradle.test.fixtures.file.TestNameTestDirectoryProvider
 import org.gradle.testkit.runner.BuildResult
@@ -83,6 +84,30 @@ class AndroidSantaTrackerSmokeTest extends AbstractSmokeTest {
         verify(relocatedResult, EXPECTED_RESULTS)
     }
 
+    def "incremental Java compilation works for Santa Tracker"() {
+        def checkoutDir = temporaryFolder.createDir ("checkout")
+        setupCopyOfSantaTracker(checkoutDir)
+
+        def pathToClass = "com/google/android/apps/santatracker/tracker/ui/BottomSheetBehavior"
+        def fileToChange = checkoutDir.file("tracker/src/main/java/${pathToClass}.java")
+        def compiledClassFile = checkoutDir.file("tracker/build/intermediates/javac/debug/classes/${pathToClass}.class")
+        def nonAbiChangeMutator = new ApplyNonAbiChangeToJavaSourceFileMutator(fileToChange)
+
+        when:
+        def result = buildLocation(checkoutDir)
+        def md5Before = compiledClassFile.md5Hash
+        then:
+        result.task(":tracker:compileDebugJavaWithJavac").outcome == SUCCESS
+
+        when:
+        nonAbiChangeMutator.beforeBuild()
+        buildLocation(checkoutDir)
+        def md5After = compiledClassFile.md5Hash
+        then:
+        result.task(":tracker:compileDebugJavaWithJavac").outcome == SUCCESS
+        md5After != md5Before
+    }
+
     private void setupCopyOfSantaTracker(TestFile targetDir) {
         copyRemoteProject("santaTracker", targetDir)
         GradleEnterprisePluginSettingsFixture.applyEnterprisePlugin(targetDir.file("settings.gradle"))