Fix a number of misc issues to allow google usage of bazel-skylib (#146)

* Fix a number of misc issues to allow google usage of bazel-skylib

1. Missing copyright header
2. Shell test fixes to use TEST_TMPDIR to have write access to directories
3. diff_test fix to use TEST_SRCDIR

* added a comment as to why diff_test_tests is local

* ran buildifier

3 files changed, 17 insertions, 0 deletions

diff --git a/tests/diff_test/BUILD b/tests/diff_test/BUILD
index bd0aacd..aa381d8 100644
--- a/tests/diff_test/BUILD
+++ b/tests/diff_test/BUILD
@@ -13,6 +13,8 @@ sh_test(
         "//rules:diff_test",
         "//tests:unittest.bash",
     ],
+    # Test marked local because it uses bazel.
+    tags = ["local"],
     deps = ["@bazel_tools//tools/bash/runfiles"],
 )
 
diff --git a/tests/diff_test/diff_test_tests.sh b/tests/diff_test/diff_test_tests.sh
index aa43307..1cab39b 100755
--- a/tests/diff_test/diff_test_tests.sh
+++ b/tests/diff_test/diff_test_tests.sh
@@ -202,4 +202,5 @@ function test_from_ext_repo_without_legacy_external_runfiles() {
   assert_from_ext_repo "--nolegacy_external_runfiles" "${FUNCNAME[0]}"
 }
 
+cd "$TEST_TMPDIR"
 run_suite "diff_test_tests test suite"
diff --git a/tests/unittest_tests.bzl b/tests/unittest_tests.bzl
index 01ea4de..e25e4da 100644
--- a/tests/unittest_tests.bzl
+++ b/tests/unittest_tests.bzl
@@ -1,3 +1,17 @@
+# Copyright 2019 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 """Unit tests for unittest.bzl."""
 
 load("//lib:unittest.bzl", "analysistest", "asserts", "unittest")