Optionally print a report URI when the Pitest task finishes

src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/AbstractPitestFunctionalSpec.groovy

@@ -67,6 +67,21 @@ abstract class AbstractPitestFunctionalSpec extends IntegrationSpec {
         """.stripIndent()
     }
 
+    protected void writeFailingPitTest(String packageDotted = 'gradle.pitest.test.hello', File baseDir = getProjectDir()) {
+        String path = 'src/test/java/' + packageDotted.replace('.', '/') + '/HelloPitTest.java'
+        File javaFile = createFile(path, baseDir)
+        javaFile << """package ${packageDotted};
+            import org.junit.Test;
+            import static org.junit.Assert.assertEquals;
+
+            public class HelloPitTest {
+                @Test public void shouldReturnInputNumber() {
+                    assertEquals(1, new HelloPit().returnInputNumber(5));
+                }
+            }
+        """.stripIndent()
+    }
+
     protected void assertStdOutOrStdErrContainsGivenText(ExecutionResult result, String textToContain) {
         //TODO: Simplify if possible - standardOutput for Gradle <5 and standardError for Gradle 5+
         assert result.standardOutput.contains(textToContain) || result.standardError.contains(textToContain)

src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/PitestPluginGeneralFunctionalSpec.groovy

@@ -78,6 +78,93 @@ class PitestPluginGeneralFunctionalSpec extends AbstractPitestFunctionalSpec {
             historyOutputLocation.size()
     }
 
+    void "report URI is not printed if test suite is not green"() {
+        given:
+            buildFile << getBasicGradlePitestConfig()
+        and:
+            writeHelloPitClass()
+            writeFailingPitTest()
+        when:
+            ExecutionResult result = runTasksWithFailure('pitest')
+        then:
+            result.wasExecuted(':pitest')
+            !result.getStandardOutput().contains('index.html')
+    }
+
+    void "timestamped report URI is printed if pitest run fails due to unmet thresholds"() {
+        given:
+            buildFile << getBasicGradlePitestConfig()
+            buildFile << """
+                pitest {
+                    mutationThreshold = 101
+                }
+            """.stripIndent()
+        and:
+            writeHelloPitClass()
+            writeHelloPitTest()
+        when:
+            ExecutionResult result = runTasksWithFailure('pitest')
+        then:
+            result.wasExecuted(':pitest')
+            result.getStandardOutput().find(/pitest.[0-9]{12}.index\.html/)
+    }
+
+    void "timestamped report URI is not printed if turned off and pitest run fails due to unmet thresholds"() {
+        given:
+            buildFile << getBasicGradlePitestConfig()
+            buildFile << """
+                pitest {
+                    mutationThreshold = 101
+                    printReportUri = 'never'
+                }
+            """.stripIndent()
+        and:
+            writeHelloPitClass()
+            writeHelloPitTest()
+        when:
+            ExecutionResult result = runTasksWithFailure('pitest')
+        then:
+            result.wasExecuted(':pitest')
+            !result.getStandardOutput().find(/pitest.[0-9]{12}.index\.html/)
+    }
+
+    void "timestamped report URI is printed if always requested and pitest run passes"() {
+        given:
+            buildFile << getBasicGradlePitestConfig()
+            buildFile << """
+                pitest {
+                    printReportUri = 'always'
+                }
+            """.stripIndent()
+        and:
+            writeHelloPitClass()
+            writeHelloPitTest()
+        when:
+            ExecutionResult result = runTasksSuccessfully('pitest')
+        then:
+            result.wasExecuted(':pitest')
+            result.getStandardOutput().find(/pitest.[0-9]{12}.index\.html/)
+    }
+
+    void "non-timestamped report URI is printed if always requested and pitest run passes"() {
+        given:
+            buildFile << getBasicGradlePitestConfig()
+            buildFile << """
+                pitest {
+                    printReportUri = 'always'
+                    timestampedReports = false
+                }
+            """.stripIndent()
+        and:
+            writeHelloPitClass()
+            writeHelloPitTest()
+        when:
+            ExecutionResult result = runTasksSuccessfully('pitest')
+        then:
+            result.wasExecuted(':pitest')
+            result.getStandardOutput().contains(quoteBackslashesInWindowsPath(new File('reports/pitest/index.html')))
+    }
+
     void "pass additional configured parameters that cannot be test with ProjectBuilder"() {
         given:
             buildFile << getBasicGradlePitestConfig()
@@ -114,7 +201,7 @@ class PitestPluginGeneralFunctionalSpec extends AbstractPitestFunctionalSpec {
 
     private String quoteBackslashesInWindowsPath(File file) {
         //There is problem with backslash within '' or "" while running this test on Windows: "unexpected char"
-        return file.absolutePath.replaceAll('\\\\', '\\\\\\\\')
+        return file.toString().replaceAll('\\\\', '\\\\\\\\')
     }
 
 }

src/main/groovy/info/solidsoft/gradle/pitest/PitestPlugin.groovy

@@ -201,6 +201,7 @@ class PitestPlugin implements Plugin<Project> {
         task.maxSurviving.set(extension.maxSurviving)
         task.useClasspathJar.set(extension.useClasspathJar)
         task.features.set(extension.features)
+        task.printReportUri.set(extension.printReportUri)
 
         configurePropertiesWithProblematicTypesForGradle5(task)
     }

src/main/groovy/info/solidsoft/gradle/pitest/PitestPluginExtension.groovy

@@ -212,6 +212,12 @@ class PitestPluginExtension {
     @Incubating
     final ListProperty<String> fileExtensionsToFilter
 
+    /**
+     * Controls when the report URI will be printed. Valid values are: 'never', 'on-failure' (default),
+     * or 'always'
+     */
+    final Property<String> printReportUri
+
     PitestPluginExtension(Project project) {
         ObjectFactory of = project.objects
         Project p = project
@@ -262,6 +268,7 @@ class PitestPluginExtension {
         useClasspathJar = of.property(Boolean)
         features = nullListPropertyOf(p, String)
         fileExtensionsToFilter = nullListPropertyOf(p, String)
+        printReportUri = of.property(String)
     }
 
     void setReportDir(File reportDir) {

src/main/groovy/info/solidsoft/gradle/pitest/PitestTask.groovy

@@ -38,6 +38,7 @@ import org.gradle.api.tasks.OutputFile
 import org.gradle.api.tasks.PathSensitive
 import org.gradle.api.tasks.PathSensitivity
 import org.gradle.api.tasks.options.Option
+import org.gradle.process.ExecResult
 
 /**
  * Gradle task implementation for Pitest.
@@ -241,6 +242,10 @@ class PitestTask extends JavaExec {
     @Optional
     List<String> overriddenTargetTests  //should be Set<String> or SetProperty but it's not supported in Gradle as of 5.6.1
 
+    @Input
+    @Optional
+    final Property<String> printReportUri
+
     PitestTask() {
         //setting during execution doesn't work in 6.4+:
         //The value for task ':pitest' property 'mainClass' is final and cannot be changed any further.
@@ -294,6 +299,7 @@ class PitestTask extends JavaExec {
         useAdditionalClasspathFile = of.property(Boolean)
         additionalClasspathFile = of.fileProperty()
         features = of.listProperty(String)
+        printReportUri = of.property(String)
     }
 
     @Input
@@ -319,12 +325,61 @@ class PitestTask extends JavaExec {
         return jvmPath.isPresent() ? jvmPath.asFile.get().absolutePath : null
     }
 
+    @SuppressWarnings('UnnecessarySetter')
     @Override
     void exec() {
         args = argumentsForPit()
         jvmArgs = ((List<String>) getMainProcessJvmArgs().getOrNull() ?: getJvmArgs())
         classpath = getLaunchClasspath()
+
+        /*
+         * As it's up to Pitest to write the report somewhere in the report dir if
+         * timestamped reports are allowed, it is necessary to figure out which one
+         * is the latest one.
+         */
+        Set<File> previousReportDirs = []
+        if (timestampedReports.getOrElse(true)) {
+            previousReportDirs = listTimestampedReportDirs(getReportDir().asFile.get())
+        }
+
+        setIgnoreExitValue(true)
         super.exec()
+        ExecResult execResult = getExecutionResult().get()
+
+        printReportUriIfNecessary(execResult.exitValue, previousReportDirs)
+
+        execResult.assertNormalExitValue()
+    }
+
+    private void printReportUriIfNecessary(int exitValue, Set<File> previousReportDirs) {
+        String printReportUri = this.printReportUri.getOrElse('on-failure')
+
+        if ((exitValue != 0 &&
+                printReportUri in ['on-failure', 'always'])
+                || printReportUri in ['always']) {
+            File indexFile = resolveReportIndexFile(previousReportDirs)
+
+            if (indexFile.exists()) {
+                getLogger().warn('See the Pitest report at: ' +
+                        new URI('file', '', indexFile.toURI().getPath(), (String) null, (String) null))
+            }
+        }
+    }
+
+    private File resolveReportIndexFile(Set<File> previousReportDirs) {
+        File actualReportDir
+
+        if (timestampedReports.getOrElse(true)) {
+            actualReportDir = (listTimestampedReportDirs(getReportDir().asFile.get()) - previousReportDirs).first()
+        } else {
+            actualReportDir = getReportDir().asFile.get()
+        }
+
+        return new File(actualReportDir, 'index.html')
+    }
+
+    private static Set<File> listTimestampedReportDirs(File reportDir) {
+        return reportDir.listFiles().findAll { file -> file.isDirectory() }.toSet()
     }
 
     private List<String> argumentsForPit() {