Adapt quick assist test suite for new quickAssists extension point

Most of the tests are bad and because they rely on UI behavior they
can't even be run by the build server. But the tests exist and I don't
want to remove them. If someone has more time available it would be
nice if this person could move tests completely away from UI classes.

org.scala-ide.sdt.core.tests/src/org/scalaide/core/quickassist/ChangeCaseTests.scala

@@ -3,7 +3,7 @@ package org.scalaide.core.quickassist
 import org.junit.Test
 
 class ChangeCaseTests {
-  import QuickFixesTests._
+  import UiQuickAssistTests._
 
   @Test def changeCase() {
     withManyQuickFixesPerLine("changecase/ChangeCase.scala")(
@@ -17,4 +17,4 @@ class ChangeCaseTests {
     )
   }
 
-}
+}

org.scala-ide.sdt.core.tests/src/org/scalaide/core/quickassist/CreateClassTests.scala

@@ -3,10 +3,10 @@ package org.scalaide.core.quickassist
 import org.junit.Test
 
 class CreateClassTests {
-  import QuickFixesTests._
+  import UiQuickAssistTests._
 
   @Test
   def createClassQuickFixes() {
     withQuickFixes("createclass/UsesMissingClass.scala")("Create class 'ThisClassDoesNotExist'")
   }
-}
+}

org.scala-ide.sdt.core.tests/src/org/scalaide/core/quickassist/TypeMismatchTests.scala

@@ -3,9 +3,9 @@ package org.scalaide.core.quickassist
 import org.junit.Test
 
 class TypeMismatchTests {
-  import QuickFixesTests._
+  import UiQuickAssistTests._
 
-  val stringPattern = "Transform expression: %s => %s"
+  val stringPattern: String = "Transform expression: %s => %s"
 
   @Test
   def basicTypeMismatchQuickFixes() {
@@ -60,4 +60,4 @@ class TypeMismatchTests {
 //        )
           ))
   }
-}
+}

org.scala-ide.sdt.core.tests/src/org/scalaide/core/quickassist/UiQuickAssistTests.scala

@@ -0,0 +1,66 @@
+package org.scalaide.core
+package quickassist
+
+import org.eclipse.jdt.core.compiler.IProblem
+import org.eclipse.jdt.ui.JavaUI
+import org.eclipse.jface.text.quickassist.IQuickAssistInvocationContext
+import org.junit.Assert._
+import org.scalaide.core.internal.jdt.model.ScalaCompilationUnit
+import org.scalaide.core.internal.quickassist.QuickAssistProcessor
+
+import testsetup.TestProjectSetup
+
+/**
+ * Provides test behavior that relies on a working UI environment.
+ */
+object UiQuickAssistTests extends TestProjectSetup("quickassist") {
+
+  def assertNumberOfProblems(nProblems: Int, problems: Array[IProblem]) {
+    if (problems.length != nProblems) {
+      val buf = new StringBuffer("Wrong number of problems, is: ")
+      buf.append(problems.length).append(", expected: ").append(nProblems).append('\n')
+      for (problem <- problems) {
+        buf.append(problem).append(" at ")
+        buf.append('[').append(problem.getSourceStart()).append(" ,").append(problem.getSourceEnd()).append(']')
+        buf.append('\n')
+      }
+
+      assertEquals(buf.toString, nProblems, problems.length)
+    }
+  }
+
+  def withQuickFixes(pathToSource: String)(expectedQuickFixes: String*) {
+    withManyQuickFixesPerLine(pathToSource)(expectedQuickFixes.map(List(_)).toList)
+  }
+
+  def withManyQuickFixesPerLine(pathToSource: String)(expectedQuickFixesList: List[List[String]]) {
+    val unit = compilationUnit(pathToSource).asInstanceOf[ScalaCompilationUnit]
+
+    unit.withSourceFile { (src, compiler) =>
+      compiler.askReload(List(unit)).get
+
+      val problems = compiler.problemsOf(unit)
+      assertTrue("No problems found.", problems.nonEmpty)
+      assertNumberOfProblems(expectedQuickFixesList.size, problems.toArray)
+
+      val part = JavaUI.openInEditor(unit.getCompilationUnit)
+
+      for ((problem, expectedQuickFixes) <- problems zip expectedQuickFixesList) {
+        val offset = problem.getSourceStart
+        val length = problem.getSourceEnd + 1 - offset
+        val processor = new QuickAssistProcessor(part.getEditorInput, QuickAssistProcessor.DefaultId)
+        val proposals = processor.computeQuickAssistProposals(new IQuickAssistInvocationContext {
+          override def getOffset = offset
+          override def getLength = length
+          override def getSourceViewer = null
+        })
+        val corrections = proposals.map(_.getDisplayString)
+
+        for (quickFix <- expectedQuickFixes) {
+          assertTrue("Quick fix " + quickFix + " was not offered. Offered were: " + corrections.mkString(", "),
+            corrections contains quickFix)
+        }
+      }
+    }
+  }
+}

org.scala-ide.sdt.core.tests/src/org/scalaide/core/quickassist/createmethod/CreateMethodTests.scala

@@ -1,10 +1,10 @@
 package org.scalaide.core.quickassist.createmethod
 
 import org.junit.Test
-import org.scalaide.core.quickassist.QuickFixesTests
+import org.scalaide.core.quickassist.UiQuickAssistTests
 
 class CreateMethodTests {
-  import QuickFixesTests._
+  import UiQuickAssistTests._
 
     @Test def createMethod() {
     withQuickFixes("createmethod/CreateMethod.scala")(