diff --git a/build.sbt b/build.sbt
index 0dfa27d2..a7e598cf 100644
--- a/build.sbt
+++ b/build.sbt
@@ -11,7 +11,7 @@ unmanagedSourceDirectories in Compile += (
   else (sourceDirectory in Compile).value / "scala-2.11_2.12"
 )
 
-crossScalaVersions := Seq("2.12.5", "2.13.0-M4-pre-20d3c21", "2.11.12")
+crossScalaVersions := Seq("2.12.5", "2.13.0-pre-b11db01", "2.11.12")
 
 scalaVersion := crossScalaVersions.value.head
 
diff --git a/src/main/scala-2.11_2.12/collection/BuildFrom.scala b/src/main/scala-2.11_2.12/scala/collection/BuildFrom.scala
similarity index 100%
rename from src/main/scala-2.11_2.12/collection/BuildFrom.scala
rename to src/main/scala-2.11_2.12/scala/collection/BuildFrom.scala
diff --git a/src/main/scala-2.11_2.12/collection/Factory.scala b/src/main/scala-2.11_2.12/scala/collection/Factory.scala
similarity index 100%
rename from src/main/scala-2.11_2.12/collection/Factory.scala
rename to src/main/scala-2.11_2.12/scala/collection/Factory.scala
diff --git a/src/main/scala-2.11_2.12/collection/compat_impl/package.scala b/src/main/scala-2.11_2.12/scala/collection/compat/CompatImpl.scala
similarity index 70%
rename from src/main/scala-2.11_2.12/collection/compat_impl/package.scala
rename to src/main/scala-2.11_2.12/scala/collection/compat/CompatImpl.scala
index 7f627e4f..91abd31a 100644
--- a/src/main/scala-2.11_2.12/collection/compat_impl/package.scala
+++ b/src/main/scala-2.11_2.12/scala/collection/compat/CompatImpl.scala
@@ -1,10 +1,10 @@
-package scala.collection
+package scala.collection.compat
 
-import scala.collection.generic._
+import scala.collection.generic.CanBuildFrom
 import scala.collection.mutable.Builder
-import scala.reflect.ClassTag
+import scala.collection.{immutable, mutable}
 
-package object compat_impl {
+private[compat] object CompatImpl {
   def simpleCBF[A, C](f: => Builder[A, C]): CanBuildFrom[Any, A, C] = new CanBuildFrom[Any, A, C] {
     def apply(from: Any): Builder[A, C] = apply()
     def apply(): Builder[A, C] = f
diff --git a/src/main/scala-2.11_2.12/collection/compat/package.scala b/src/main/scala-2.11_2.12/scala/collection/compat/package.scala
similarity index 90%
rename from src/main/scala-2.11_2.12/collection/compat/package.scala
rename to src/main/scala-2.11_2.12/scala/collection/compat/package.scala
index 75efe169..69f4aa14 100644
--- a/src/main/scala-2.11_2.12/collection/compat/package.scala
+++ b/src/main/scala-2.11_2.12/scala/collection/compat/package.scala
@@ -6,7 +6,7 @@ import scala.reflect.ClassTag
 
 /** The collection compatibility API */
 package object compat {
-  import scala.collection.compat_impl._
+  import CompatImpl._
 
   implicit def genericCompanionToCBF[A, CC[X] <: GenTraversable[X]](fact: GenericCompanion[CC]): CanBuildFrom[Any, A, CC[A]] =
     simpleCBF(fact.newBuilder[A])
@@ -48,6 +48,12 @@ package object compat {
     def lazyAppendAll(as: => TraversableOnce[A]): Stream[A] = stream.append(as)
   }
 
+  implicit class SortedExtensionMethods[K, T <: Sorted[K, T]](private val fact: Sorted[K, T]) {
+    def rangeFrom(from: K): T = fact.from(from)
+    def rangeTo(to: K): T = fact.to(to)
+    def rangeUntil(until: K): T = fact.until(until)
+  }
+
   // This really belongs into scala.collection but there's already a package object in scala-library so we can't add to it
   type IterableOnce[+X] = TraversableOnce[X]
 }
diff --git a/src/main/scala-2.11_2.12/collection/immutable/ImmutableArray.scala b/src/main/scala-2.11_2.12/scala/collection/immutable/ImmutableArray.scala
similarity index 100%
rename from src/main/scala-2.11_2.12/collection/immutable/ImmutableArray.scala
rename to src/main/scala-2.11_2.12/scala/collection/immutable/ImmutableArray.scala
diff --git a/src/test/scala/collection/BuildFromTest.scala b/src/test/scala/test/scala/collection/BuildFromTest.scala
similarity index 96%
rename from src/test/scala/collection/BuildFromTest.scala
rename to src/test/scala/test/scala/collection/BuildFromTest.scala
index e0ffe2f6..2de26ef1 100644
--- a/src/test/scala/collection/BuildFromTest.scala
+++ b/src/test/scala/test/scala/collection/BuildFromTest.scala
@@ -1,10 +1,11 @@
-package scala.collection
+package test.scala.collection
 
 import org.junit.Test
 
-import scala.collection.mutable.{ArrayBuffer, Builder, ListBuffer}
-import scala.collection.immutable.{HashMap, List, TreeMap, TreeSet}
 import scala.collection.compat._
+import scala.collection.immutable.{HashMap, TreeMap, TreeSet}
+import scala.collection.mutable.{ArrayBuffer, Builder, ListBuffer}
+import scala.collection.{BitSet, BuildFrom, SortedMap, SortedSet, immutable, mutable}
 
 // Tests copied from the 2.13 scala-library
 class BuildFromTest {
diff --git a/src/test/scala/collection/CollectionTest.scala b/src/test/scala/test/scala/collection/CollectionTest.scala
similarity index 97%
rename from src/test/scala/collection/CollectionTest.scala
rename to src/test/scala/test/scala/collection/CollectionTest.scala
index f91d8283..65217af5 100644
--- a/src/test/scala/collection/CollectionTest.scala
+++ b/src/test/scala/test/scala/collection/CollectionTest.scala
@@ -1,12 +1,10 @@
-package collection
+package test.scala.collection
 
-import java.util
-
-import org.junit.Test
 import org.junit.Assert._
+import org.junit.Test
 
-import scala.collection.immutable.BitSet
 import scala.collection.compat._
+import scala.collection.immutable.BitSet
 
 class CollectionTest {
   @Test
diff --git a/src/test/scala/collection/FactoryTest.scala b/src/test/scala/test/scala/collection/FactoryTest.scala
similarity index 86%
rename from src/test/scala/collection/FactoryTest.scala
rename to src/test/scala/test/scala/collection/FactoryTest.scala
index 5ea2dd0c..84e1c027 100644
--- a/src/test/scala/collection/FactoryTest.scala
+++ b/src/test/scala/test/scala/collection/FactoryTest.scala
@@ -1,15 +1,15 @@
-package collection
+package test.scala.collection
 
 import org.junit.{Assert, Test}
 
-import scala.collection.{BitSet, Factory, Iterable, immutable, mutable}
 import scala.collection.compat._
+import scala.collection.{BitSet, Factory, immutable, mutable}
 
 class FactoryTest {
 
   implicitly[Factory[Char, String]]
   implicitly[Factory[Char, Array[Char]]]
-  implicitly[Factory[Int, BitSet]]
+  implicitly[Factory[Int, collection.BitSet]]
   implicitly[Factory[Int, mutable.BitSet]]
   implicitly[Factory[Int, immutable.BitSet]]
 
diff --git a/src/test/scala/collection/ImmutableArrayTest.scala b/src/test/scala/test/scala/collection/ImmutableArrayTest.scala
similarity index 98%
rename from src/test/scala/collection/ImmutableArrayTest.scala
rename to src/test/scala/test/scala/collection/ImmutableArrayTest.scala
index 3d7984a3..6e67ce21 100644
--- a/src/test/scala/collection/ImmutableArrayTest.scala
+++ b/src/test/scala/test/scala/collection/ImmutableArrayTest.scala
@@ -1,4 +1,4 @@
-package collection
+package test.scala.collection
 
 import org.junit.{Assert, Test}
 
diff --git a/src/test/scala/collection/StreamTest.scala b/src/test/scala/test/scala/collection/StreamTest.scala
similarity index 87%
rename from src/test/scala/collection/StreamTest.scala
rename to src/test/scala/test/scala/collection/StreamTest.scala
index 31837699..3b308b5f 100644
--- a/src/test/scala/collection/StreamTest.scala
+++ b/src/test/scala/test/scala/collection/StreamTest.scala
@@ -1,4 +1,4 @@
-package collection
+package test.scala.collection
 
 import org.junit.Test
 
diff --git a/src/test/scala/test/scala/collection/generic/SortedTest.scala b/src/test/scala/test/scala/collection/generic/SortedTest.scala
new file mode 100644
index 00000000..5e0a30fd
--- /dev/null
+++ b/src/test/scala/test/scala/collection/generic/SortedTest.scala
@@ -0,0 +1,55 @@
+package test.scala.collection.generic
+
+import org.junit.Assert._
+import org.junit.Test
+
+import scala.collection.compat._
+import scala.collection.{immutable => i, mutable => m}
+
+class SortedTest {
+  @Test
+  def immutableRangeOps(): Unit = {
+    val st = i.SortedSet(-1, 2, 4, 3)
+    for (x <- List(0, 1, 4, -1, -4)) {
+      val s1 = st.rangeFrom(x)
+      assertEquals(s1: i.SortedSet[Int], st.from(x))
+      val s2 = st.rangeTo(x)
+      assertEquals(s2: i.SortedSet[Int], st.to(x))
+      val s3 = st.rangeUntil(x)
+      assertEquals(s3: i.SortedSet[Int], st.until(x))
+    }
+    val mp = i.SortedMap("" -> 0, "ds" -> -3, "-??" -> 13, "Df" -> 33, "d!" -> -32)
+    for (x <- List("", "-", "@", "aa", "D", "d")) {
+      val m1 = mp.rangeFrom(x)
+      assertEquals(m1: i.SortedMap[String, Int], mp.from(x))
+      val m2 = mp.rangeTo(x)
+      assertEquals(m2: i.SortedMap[String, Int], mp.to(x))
+      val m3 = mp.rangeUntil(x)
+      assertEquals(m3: i.SortedMap[String, Int], mp.until(x))
+    }
+  }
+
+  @Test
+  def mutableRangeOps(): Unit = {
+    val st = m.SortedSet(-1, 2, 4, 3)
+    for (x <- List(0, 1, 4, -1, -4)) {
+      val s1 = st.rangeFrom(x)
+      assertEquals(s1: m.SortedSet[Int], st.from(x))
+      val s2 = st.rangeTo(x)
+      assertEquals(s2: m.SortedSet[Int], st.to(x))
+      val s3 = st.rangeUntil(x)
+      assertEquals(s3: m.SortedSet[Int], st.until(x))
+    }
+    /* 2.11 doesn't have a mutable.SortedMap
+    val mp = m.SortedMap("" -> 0, "ds" -> -3, "-??" -> 13, "Df" -> 33, "d!" -> -32)
+    for (x <- List("", "-", "@", "aa", "D", "d")) {
+      val m1 = mp.rangeFrom(x)
+      assertEquals(m1: m.SortedMap[String, Int], mp.from(x))
+      val m2 = mp.rangeTo(x)
+      assertEquals(m2: m.SortedMap[String, Int], mp.to(x))
+      val m3 = mp.rangeUntil(x)
+      assertEquals(m3: m.SortedMap[String, Int], mp.until(x))
+    }
+    */
+  }
+}