From de1c5a4aedd27bb880e33e519d636e2607b35412 Mon Sep 17 00:00:00 2001
From: Grzegorz Kossakowski <grzegorz.kossakowski@gmail.com>
Date: Sun, 24 Nov 2013 23:27:54 +0100
Subject: [PATCH] Add support for unit testing of extracted source
 dependencies.

Add `extractDependenciesFromSrcs` method to ScalaCompilerForUnitTest
class which allows us to unit test dependency extraction logic.

See the comment attached to the method that explain the details of
how it should be used.
---
 .../xsbt/ScalaCompilerForUnitTesting.scala    | 53 ++++++++++++++++---
 1 file changed, 46 insertions(+), 7 deletions(-)

diff --git a/compile/interface/src/test/scala/xsbt/ScalaCompilerForUnitTesting.scala b/compile/interface/src/test/scala/xsbt/ScalaCompilerForUnitTesting.scala
index 8b4d67d23..61fb08078 100644
--- a/compile/interface/src/test/scala/xsbt/ScalaCompilerForUnitTesting.scala
+++ b/compile/interface/src/test/scala/xsbt/ScalaCompilerForUnitTesting.scala
@@ -13,11 +13,13 @@ import xsbti.api.Def
 import xsbt.api.SameAPI
 import sbt.ConsoleLogger
 
+import ScalaCompilerForUnitTesting.ExtractedSourceDependencies
+
 /**
  * Provides common functionality needed for unit tests that require compiling
  * source code using Scala compiler.
  */
-class ScalaCompilerForUnitTesting {
+class ScalaCompilerForUnitTesting(memberRefAndInheritanceDeps: Boolean = false) {
 
 	/**
 	 * Compiles given source code using Scala compiler and returns API representation
@@ -28,6 +30,43 @@ class ScalaCompilerForUnitTesting {
 		analysisCallback.apis(tempSrcFile)
 	}
 
+	/**
+	 * Compiles given source code snippets (passed as Strings) using Scala compiler and returns extracted
+	 * dependencies between snippets. Source code snippets are identified by symbols. Each symbol should
+	 * be associated with one snippet only.
+	 *
+	 * Symbols are used to express extracted dependencies between source code snippets. This way we have
+	 * file system-independent way of testing dependencies between source code "files".
+	 */
+	def extractDependenciesFromSrcs(srcs: (Symbol, String)*): ExtractedSourceDependencies = {
+		val (symbolsForSrcs, rawSrcs) = srcs.unzip
+		assert(symbolsForSrcs.distinct.size == symbolsForSrcs.size,
+			s"Duplicate symbols for srcs detected: $symbolsForSrcs")
+		val (tempSrcFiles, testCallback) = compileSrcs(rawSrcs: _*)
+		val fileToSymbol = (tempSrcFiles zip symbolsForSrcs).toMap
+		val memberRefFileDeps =  testCallback.sourceDependencies collect {
+			// false indicates that those dependencies are not introduced by inheritance
+			case (target, src, false) => (src, target)
+		}
+		val inheritanceFileDeps =  testCallback.sourceDependencies collect {
+			// true indicates that those dependencies are introduced by inheritance
+			case (target, src, true) => (src, target)
+		}
+		def toSymbols(src: File, target: File): (Symbol, Symbol) = (fileToSymbol(src), fileToSymbol(target))
+		val memberRefDeps = memberRefFileDeps map { case (src, target) => toSymbols(src, target) }
+		val inheritanceDeps = inheritanceFileDeps map { case (src, target) => toSymbols(src, target) }
+		def pairsToMultiMap[A, B](pairs: Seq[(A, B)]): Map[A, Set[B]] = {
+			import scala.collection.mutable.{HashMap, MultiMap}
+			val emptyMultiMap = new HashMap[A, scala.collection.mutable.Set[B]] with MultiMap[A, B]
+			val multiMap = pairs.foldLeft(emptyMultiMap) { case (acc, (key, value)) =>
+				acc.addBinding(key, value)
+			}
+			// convert all collections to immutable variants
+			multiMap.toMap.mapValues(_.toSet).withDefaultValue(Set.empty)
+		}
+		ExtractedSourceDependencies(pairsToMultiMap(memberRefDeps), pairsToMultiMap(inheritanceDeps))
+	}
+
 	/**
 	 * Compiles given source code snippets written to a temporary files. Each snippet is
 	 * written to a separate temporary file.
@@ -37,7 +76,7 @@ class ScalaCompilerForUnitTesting {
 	 */
 	private def compileSrcs(srcs: String*): (Seq[File], TestCallback) = {
 		withTemporaryDirectory { temp =>
-			val analysisCallback = new TestCallback
+			val analysisCallback = new TestCallback(memberRefAndInheritanceDeps)
 			val classesDir = new File(temp, "classes")
 			classesDir.mkdir()
 			val compiler = prepareCompiler(classesDir, analysisCallback)
@@ -53,12 +92,8 @@ class ScalaCompilerForUnitTesting {
 	}
 
 	private def prepareSrcFile(baseDir: File, fileName: String, src: String): File = {
-		import java.io.FileWriter
 		val srcFile = new File(baseDir, fileName)
-		srcFile.createNewFile()
-		val fw = new FileWriter(srcFile)
-		fw.write(src)
-		fw.close()
+		sbt.IO.write(srcFile, src)
 		srcFile
 	}
 
@@ -90,3 +125,7 @@ class ScalaCompilerForUnitTesting {
 	}
 
 }
+
+object ScalaCompilerForUnitTesting {
+	case class ExtractedSourceDependencies(memberRef: Map[Symbol, Set[Symbol]], inheritance: Map[Symbol, Set[Symbol]])
+}