Auto add kotlin source dirs when present

The jetbrains kotlin plugin doesn't seem to use the source dirs
configured in the maven model. Many projects will therefore not
have them properly configured. This hack ensures pitest picks them
up if they are present.

pitest-maven/src/main/java/org/pitest/maven/MojoToReportOptionsConverter.java

@@ -30,6 +30,7 @@
 
 import java.io.File;
 import java.nio.file.FileSystems;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.ArrayList;
@@ -44,6 +45,7 @@
 import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 public class MojoToReportOptionsConverter {
 
@@ -135,6 +137,7 @@ private ReportOptions parseReportOptions(final List<String> classPath) {
     final List<String> sourceRoots = new ArrayList<>();
     sourceRoots.addAll(this.mojo.getProject().getCompileSourceRoots());
     sourceRoots.addAll(this.mojo.getProject().getTestCompileSourceRoots());
+    sourceRoots.addAll(kotlinIfPresent());
 
     data.setSourceDirs(stringsToPaths(sourceRoots));
 
@@ -170,6 +173,17 @@ private ReportOptions parseReportOptions(final List<String> classPath) {
     return data;
   }
 
+  // Many maven projects will not have the kotlin sources dirs configured within the maven
+  // model. To work around this, the horrible hack below adds them if they are present
+  private Collection<String> kotlinIfPresent() {
+    Path test = Paths.get(this.mojo.getProject().getBasedir().getAbsolutePath(),"src","test","kotlin" );
+    Path main = Paths.get(this.mojo.getProject().getBasedir().getAbsolutePath(),"src","main","kotlin" );
+    return Stream.of(test, main)
+            .filter(Files::exists)
+            .map(p -> p.toFile().getAbsolutePath())
+            .collect(Collectors.toList());
+  }
+
   private void configureVerbosity(ReportOptions data) {
     if (this.mojo.isVerbose()) {
       data.setVerbosity(Verbosity.VERBOSE);

pitest-maven/src/test/java/org/pitest/maven/MojoToReportOptionsConverterTest.java

@@ -20,13 +20,17 @@
 import org.apache.maven.model.Model;
 import org.apache.maven.model.Plugin;
 import org.codehaus.plexus.util.xml.Xpp3Dom;
+import org.junit.rules.TemporaryFolder;
 import org.mockito.Mockito;
 import org.pitest.mutationtest.config.ConfigOption;
 import org.pitest.mutationtest.config.ReportOptions;
 import org.pitest.util.Unchecked;
 
 import java.io.File;
+import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -66,6 +70,7 @@ public void setUp() throws Exception {
     Build build = new Build();
     build.setOutputDirectory("");
     when(this.project.getBuild()).thenReturn(build);
+    when(this.project.getBasedir()).thenReturn(new File("BASEDIR"));
   }
 
   public void testsParsesReportDir() {
@@ -444,6 +449,29 @@ public void testEvaluatesArgLineProperties() {
     assertThat(actual.getArgLine()).isEqualTo("fooValue barValue");
   }
 
+  public void testAutoAddsKotlinSourceDirsWhenPresent() throws IOException {
+    // we're stuck in junit 3 land but can
+    // use junit 4's temporary folder rule programatically
+    TemporaryFolder t = new TemporaryFolder();
+    try {
+      t.create();
+      File base = t.getRoot();
+      when(project.getBasedir()).thenReturn(base);
+
+      Path main = base.toPath().resolve("src").resolve("main").resolve("kotlin");
+      Path test = base.toPath().resolve("src").resolve("test").resolve("kotlin");
+      Files.createDirectories(main);
+      Files.createDirectories(test);
+
+      ReportOptions actual = parseConfig("");
+      assertThat(actual.getSourcePaths()).contains(main);
+    } finally {
+      t.delete();
+    }
+
+  }
+
+
   private ReportOptions parseConfig(final String xml) {
     try {
       final String pom = createPomWithConfiguration(xml);

pitest-maven/src/test/java/org/pitest/maven/PitMojoTest.java

@@ -34,6 +34,7 @@ public void setUp() throws Exception {
     super.setUp();
 
     when(this.project.getExecutionProject()).thenReturn(executionProject);
+    when(this.project.getBasedir()).thenReturn(new File("BASEDIR"));
     when(this.executionProject.getBasedir()).thenReturn(new File("BASEDIR"));
   }