Add scala_test to load

--
Change-Id: Ifbbda9bb01cd2d7350521183b7754c5004b2ab3d
Reviewed-on: https://github.com/bazelbuild/bazel/pull/862
MOS_MIGRATED_REVID=114213645
diff --git a/tools/build_defs/scala/scala.bzl b/tools/build_defs/scala/scala.bzl
index 10ac1ae..452dc92 100644
--- a/tools/build_defs/scala/scala.bzl
+++ b/tools/build_defs/scala/scala.bzl
@@ -252,7 +252,7 @@
   implementation=_scala_test_impl,
   attrs={
       "main_class": attr.string(default="org.scalatest.tools.Runner"),
-      "suites": attr.string_list(),
+      "suites": attr.string_list(non_empty=True, mandatory=True),
       "_scalatest": attr.label(executable=True, default=Label("@scalatest//file"), single_file=True, allow_files=True),
       "_java": attr.label(executable=True, default=Label("@bazel_tools//tools/jdk:java"), single_file=True, allow_files=True),
       } + _implicit_deps + _common_attrs,
diff --git a/tools/build_defs/scala/test/BUILD b/tools/build_defs/scala/test/BUILD
index 6f77bb4..699bb5a 100644
--- a/tools/build_defs/scala/test/BUILD
+++ b/tools/build_defs/scala/test/BUILD
@@ -1,4 +1,4 @@
-load("//tools/build_defs/scala:scala.bzl", "scala_binary", "scala_library")
+load("//tools/build_defs/scala:scala.bzl", "scala_binary", "scala_library", "scala_test")
 
 # The examples below show how to combine Scala and Java rules.
 # ScalaBinary is the Scala equivalent of JavaBinary.