1 files changed, 109 insertions, 0 deletions
diff --git a/test/junit/scala/tools/nsc/interpreter/CompletionTest.scala b/test/junit/scala/tools/nsc/interpreter/CompletionTest.scala
new file mode 100644
index 0000000000..70cb2882ba
--- /dev/null
+++ b/test/junit/scala/tools/nsc/interpreter/CompletionTest.scala
@@ -0,0 +1,109 @@
+package scala.tools.nsc.interpreter
+
+import java.io.{StringWriter, PrintWriter}
+
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+import scala.tools.nsc.Settings
+
+class CompletionTest {
+  val EmptyString = "" // def string results include the empty string so that JLine won't insert "def ..." at the cursor
+
+  def newIMain(): IMain = {
+    val settings = new Settings()
+    settings.Xnojline.value = true
+    settings.usejavacp.value = true
+
+    val writer = new StringWriter
+    val out = new PrintWriter(writer)
+    new IMain(settings, out)
+  }
+  @Test
+  def t4438_arrayCompletion(): Unit = {
+    val intp = newIMain()
+    val completer = new PresentationCompilerCompleter(intp)
+    assert(completer.complete("Array(1, 2, 3) rev").candidates.contains("reverseMap"))
+  }
+
+  @Test
+  def completions(): Unit = {
+    val intp = newIMain()
+    val completer = new PresentationCompilerCompleter(intp)
+    checkExact(completer, "object O { def x_y_z = 1 }; import O._; x_y")("x_y_z")
+    checkExact(completer, "object O { private def x_y_z = 1 }; import O._; x_y")()
+    checkExact(completer, "object O { private def x_y_z = 1; x_y", "}")("x_y_z")
+    checkExact(completer, "object x_y_z; import x_y")("x_y_z")
+
+    checkExact(completer, "object x_y_z { def a_b_c }; import x_y_z.a_b")("a_b_c")
+
+    checkExact(completer, "object X { private[this] def definition = 0; def")("definition")
+
+    // stable terms are offered in type completion as they might be used as a prefix
+    checkExact(completer, """object O { def x_y_z = 0; val x_z_y = ""; type T = x_""")("x_z_y")
+    checkExact(completer, """def method { def x_y_z = 0; val x_z_y = ""; type T = x_""")("x_z_y")
+  }
+
+  @Test
+  def previousLineCompletions(): Unit = {
+    val intp = newIMain()
+    intp.interpret("class C { val x_y_z = 42 }")
+    intp.interpret("object O { type T = Int }")
+
+    val completer = new PresentationCompilerCompleter(intp)
+
+    checkExact(completer, "new C().x_y")("x_y_z")
+    checkExact(completer, "(1 : O.T).toCha")("toChar")
+  }
+
+  @Test
+  def previousResultInvocation(): Unit = {
+    val intp = newIMain()
+    intp.interpret("1 + 1")
+
+    val completer = new PresentationCompilerCompleter(intp)
+
+    checkExact(completer, ".toCha")("toChar")
+  }
+
+  @Test
+  def defString(): Unit = {
+    val intp = newIMain()
+    val completer = new PresentationCompilerCompleter(intp)
+
+    // Double Tab on a fully typed selection shows the def string
+    checkExact(completer, "(p: {def a_b_c: Int}) => p.a_b_c")()
+    checkExact(completer, "(p: {def a_b_c: Int}) => p.a_b_c")(EmptyString, "def a_b_c: Int")
+
+    // likewise for an ident
+    checkExact(completer, "(p: {def x_y_z: Int}) => {import p._; x_y_z")()
+    checkExact(completer, "(p: {def x_y_z: Int}) => {import p._; x_y_z")(EmptyString, "def x_y_z: Int")
+
+    // If the first completion only gives one alternative
+    checkExact(completer, "(p: {def x_y_z: Int; def x_y_z(a: String): Int }) => p.x_y")("x_y_z")
+    // ... it is automatically inserted into the buffer. Hitting <TAB> again is triggers the help
+    checkExact(completer, "(p: {def x_y_z: Int; def x_y_z(a: String): Int }) => p.x_y_z")(EmptyString, "def x_y_z(a: String): Int", "def x_y_z: Int")
+
+    checkExact(completer, "(p: {def x_y_z: Int; def x_z_y(a: String): Int }) => p.x_")("x_y_z", "x_z_y")
+    // By contrast, in this case the user had to type "y_z" manually, so no def string printing just yet
+    checkExact(completer, "(p: {def x_y_z: Int; def x_z_y(a: String): Int }) => p.x_y_z")()
+    // Another <TAB>, Okay, time to print.
+    checkExact(completer, "(p: {def x_y_z: Int; def x_z_y(a: String): Int }) => p.x_y_z")(EmptyString, "def x_y_z: Int")
+
+    // The def string reconstructs the source-level modifiers (rather than showing the desugarings of vals),
+    // and performs as-seen-from with respect to the prefix
+    checkExact(completer, "trait T[A]{ lazy val x_y_z: A }; class C extends T[Int] { x_y_z")()
+    checkExact(completer, "trait T[A]{ lazy val x_y_z: A }; class C extends T[Int] { x_y_z")(EmptyString, "lazy val x_y_z: Int")
+  }
+
+  @Test
+  def treePrint(): Unit = {
+    val intp = newIMain()
+    val completer = new PresentationCompilerCompleter(intp)
+    checkExact(completer, " 1.toHexString //print")(EmptyString, "scala.Predef.intWrapper(1).toHexString // : String")
+  }
+
+  def checkExact(completer: PresentationCompilerCompleter, before: String, after: String = "")(expected: String*): Unit = {
+    assertEquals(expected.toSet, completer.complete(before, after).candidates.toSet)
+  }
+}