Add more tests to gradle plugin, and close spotbugs#320 (spotbugs#337)

* add test to find problem like spotbugs#320

* close spotbugs#320: iterate ClassesDirs to find all target files

* install not only spotbugs but also others

* move timing to install

* use both of central and local as repository

* update CHANGELOG

* Revert "move timing to install"

This reverts commit e997efb.

* refs spotbugs#337: extract shared logic to Before method

* refs spotbugs#337: add more tests

* shorten test by deleting temporal File object in field

* generate plugin classpath by gradle

this change lets us stop invoking `install` task before the `test`.

* Revert "generate plugin classpath by gradle"

This reverts commit 9952aa6.

.travis.yml

@@ -45,6 +45,8 @@ install:
   - rm -rf eclipse
   - tar xzvf deps/eclipse-SDK-4.6.3-linux-gtk-x86_64.tar.gz eclipse
   - echo eclipseRoot.dir=$(pwd)/eclipse > eclipsePlugin/local.properties
+  # To run gradlePlugin:test, we need to install spotbugs and its dependencies into local repository
+  - ./gradlew install -x test
 
 script:
   # Manually switch to JDK9 if needed

gradlePlugin/src/main/java/com/github/spotbugs/SpotBugsPlugin.java

@@ -7,13 +7,18 @@
 import java.net.URL;
 import java.util.Collection;
 import java.util.Properties;
+import java.util.Set;
 import java.util.concurrent.Callable;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
 
 import org.gradle.api.Action;
 import org.gradle.api.artifacts.Configuration;
 import org.gradle.api.artifacts.DependencySet;
+import org.gradle.api.file.ConfigurableFileTree;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.internal.ConventionMapping;
+import org.gradle.api.internal.file.collections.SimpleFileCollection;
 import org.gradle.api.plugins.quality.CodeQualityExtension;
 import org.gradle.api.plugins.quality.internal.AbstractCodeQualityPlugin;
 import org.gradle.api.reporting.SingleFileReport;
@@ -191,9 +196,16 @@ protected void configureForSourceSet(final SourceSet sourceSet, SpotBugsTask tas
         taskMapping.map("classes", new Callable<FileCollection>() {
             @Override
             public FileCollection call() {
-                // the simple "classes = sourceSet.output" may lead to non-existing resources directory
-                // being passed to SpotBugs Ant task, resulting in an error
-                return project.fileTree(sourceSet.getOutput().getClassesDir()).builtBy(sourceSet.getOutput());
+                Set<File> files = StreamSupport.stream(sourceSet.getOutput().getClassesDirs().spliterator(), false)
+                        .map(dir -> {
+                            // the simple "classes = sourceSet.output" may lead to non-existing resources directory
+                            // being passed to SpotBugs Ant task, resulting in an error
+                            return project.fileTree(dir).builtBy(sourceSet.getOutput());
+                        })
+                        .map(ConfigurableFileTree::spliterator)
+                        .flatMap(spliterator -> StreamSupport.stream(spliterator, false))
+                        .collect(Collectors.toSet());
+                return new SimpleFileCollection(files);
             }
         });
         taskMapping.map("classpath", new Callable<FileCollection>() {

gradlePlugin/src/test/java/com/github/spotbugs/SpotBugsPluginTest.java

@@ -4,12 +4,17 @@
 import static org.hamcrest.CoreMatchers.notNullValue;
 
 import java.io.File;
+import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
+import java.util.Optional;
 
 import org.gradle.testkit.runner.BuildResult;
+import org.gradle.testkit.runner.BuildTask;
 import org.gradle.testkit.runner.GradleRunner;
+import org.gradle.testkit.runner.TaskOutcome;
 import org.junit.Assert;
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
@@ -19,32 +24,72 @@
 public class SpotBugsPluginTest extends Assert{
   @Rule
   public TemporaryFolder folder= new TemporaryFolder();
-
-  @Test
-  public void TestSpotBugsTasksExist() throws Exception{
-    String buildScript = "plugins {\n" + 
-        "  id 'java'\n" +
-        "  id 'com.github.spotbugs'\n" + 
-        "}\n" + 
-        "version = 1.0\n" + 
-        "repositories {\n" + 
-        "  mavenCentral()\n" + 
-        "}";
-
-    File sourceDir = folder.newFolder("src", "main", "java");
-    File to = new File(sourceDir, "foo.java");
-    File from = new File("src/test/java/com/github/spotbugs/Foo.java");
-    Files.copy(from, to);
-
+
+  @Before
+  public void createProject() throws IOException {
+    String buildScript = "plugins {\n" +
+      "  id 'java'\n" +
+      "  id 'com.github.spotbugs'\n" +
+      "}\n" +
+      "version = 1.0\n" +
+      "repositories {\n" +
+      "  mavenCentral()\n" +
+      "  mavenLocal()\n" +
+      "}";
     File buildFile = folder.newFile("build.gradle");
     Files.write(buildScript.getBytes(StandardCharsets.UTF_8), buildFile);
 
+    File sourceDir = folder.newFolder("src", "main", "java");
+    File to = new File(sourceDir, "Foo.java");
+    File from = new File("src/test/java/com/github/spotbugs/Foo.java");
+    Files.copy(from, to);
+  }
 
+  @Test
+  public void TestSpotBugsTasksExist() throws Exception{
     BuildResult result = GradleRunner.create().withProjectDir(folder.getRoot()).withArguments(Arrays.asList("tasks", "--all")).withPluginClasspath().build();
     assertTrue(result.getOutput().contains("spotbugsMain"));
     assertTrue(result.getOutput().contains("spotbugsTest"));
   }
 
+  @Test
+  public void testSpotBugsTaskCanRun() throws Exception {
+    BuildResult result = GradleRunner.create()
+            .withProjectDir(folder.getRoot())
+            .withArguments(Arrays.asList("compileJava", "spotbugsMain"))
+            .withPluginClasspath().build();
+    Optional<BuildTask> spotbugsMain = findTask(result, ":spotbugsMain");
+    assertTrue(spotbugsMain.isPresent());
+    assertThat(spotbugsMain.get().getOutcome(), is(TaskOutcome.SUCCESS));
+  }
+
+  @Test
+  public void testSpotBugsTestTaskCanRun() throws Exception {
+    BuildResult result = GradleRunner.create()
+            .withProjectDir(folder.getRoot())
+            .withArguments(Arrays.asList("compileTestJava", "spotbugsTest"))
+            .withPluginClasspath().build();
+    Optional<BuildTask> spotbugsTest = findTask(result, ":spotbugsTest");
+    assertTrue(spotbugsTest.isPresent());
+    assertThat(spotbugsTest.get().getOutcome(), is(TaskOutcome.NO_SOURCE));
+  }
+
+  @Test
+  public void testCheckTaskDependsOnSpotBugsTasks() throws Exception {
+    BuildResult result = GradleRunner.create()
+            .withProjectDir(folder.getRoot())
+            .withArguments(Arrays.asList("compileJava", "compileTestJava", "check"))
+            .withPluginClasspath().build();
+    assertTrue(findTask(result, ":spotbugsMain").isPresent());
+    assertTrue(findTask(result, ":spotbugsTest").isPresent());
+  }
+
+  private Optional<BuildTask> findTask(BuildResult result, String taskName) {
+    return result.getTasks().stream()
+          .filter(task -> task.getPath().equals(taskName))
+          .findAny();
+  }
+
   @Test
   public void testLoadToolVersion() {
     SpotBugsPlugin plugin = new SpotBugsPlugin();