Add tests on sourcePositionMappers

sbt/src/sbt-test/reporter/source-mapper/build.sbt

@@ -0,0 +1,46 @@
+import java.util.Optional
+import xsbti.Position
+
+val assertAbsolutePathConversion = taskKey[Unit]("checks source mappers convert to absolute path")
+
+val assertHandleFakePos = taskKey[Unit]("checks source mappers handle fake position")
+
+assertAbsolutePathConversion := {
+  val converter = fileConverter.value
+  val source = (Compile/sources).value.head
+  val position = newPosition(converter.toVirtualFile(source.toPath).id, source)
+  val mappedPos = sourcePositionMappers.value
+    .foldLeft(Option(position)) {
+      case (pos, mapper) => pos.flatMap(mapper)
+    }
+  assert {
+    mappedPos.get.sourcePath.asScala.contains(source.getAbsolutePath)
+  }
+}
+
+assertHandleFakePos := {
+  val position = newPosition("<macro>", new File("<macro>"))
+  val mappedPos = sourcePositionMappers.value
+    .foldLeft(Option(position)) {
+      case (pos, mapper) => pos.flatMap(mapper)
+    }
+  assert {
+    mappedPos.get.sourcePath.asScala.get.contains("<macro>")
+  }
+}
+
+def newPosition(path: String, file: File): Position = new Position {
+  override def line(): Optional[Integer] = Optional.empty()
+
+  override def lineContent() = ""
+
+  override def offset(): Optional[Integer] = Optional.empty()
+
+  override def pointer(): Optional[Integer] = Optional.empty()
+
+  override def pointerSpace(): Optional[String] = Optional.empty()
+
+  override def sourcePath(): Optional[String] = Optional.of(path)
+
+  override def sourceFile(): Optional[File] = Optional.of(file)
+}

sbt/src/sbt-test/reporter/source-mapper/test

@@ -0,0 +1,2 @@
+> assertAbsolutePathConversion
+> assertHandleFakePos