Address skylint warnings on the tests. (#39)

* Skylint: Move comment out of docstring.

Is skylint seems more than a single like docstring, it expect a full comment
with Args/Returns/etc.; avoid having to have full docstring but just making
the comment a comment and not part of the docstring.

* Address some skylint issues.

- ctx.file_action -> ctx.actions.write
- Return an empty list of providers rather then an old style empty struct.

3 files changed, 12 insertions, 14 deletions

diff --git a/tests/new_sets_tests.bzl b/tests/new_sets_tests.bzl
index 214d1c2..5734fb7 100644
--- a/tests/new_sets_tests.bzl
+++ b/tests/new_sets_tests.bzl
@@ -18,12 +18,11 @@ load("//:lib.bzl", "new_sets", "asserts", "unittest")
 
 
 def _is_equal_test(ctx):
-  """Unit tests for new_sets.is_equal.
+  """Unit tests for new_sets.is_equal."""
 
-  Note that if this test fails, the results for the other `sets` tests will be
-  inconclusive because they use `asserts.new_set_equals`, which in turn calls
-  `new_sets.is_equal`.
-  """
+  # Note that if this test fails, the results for the other `sets` tests will
+  # be inconclusive because they use `asserts.new_set_equals`, which in turn
+  # calls `new_sets.is_equal`.
   env = unittest.begin(ctx)
 
   asserts.true(env, new_sets.is_equal(new_sets.make(), new_sets.make()))
@@ -264,4 +263,4 @@ def new_sets_test_suite():
       contains_test,
       length_test,
       remove_test,
-  )
\ No newline at end of file
+  )
diff --git a/tests/sets_tests.bzl b/tests/sets_tests.bzl
index 8c64396..bddab69 100644
--- a/tests/sets_tests.bzl
+++ b/tests/sets_tests.bzl
@@ -18,12 +18,11 @@ load("//:lib.bzl", "sets", "asserts", "unittest")
 
 
 def _is_equal_test(ctx):
-  """Unit tests for sets.is_equal.
+  """Unit tests for sets.is_equal."""
 
-  Note that if this test fails, the results for the other `sets` tests will be
-  inconclusive because they use `asserts.set_equals`, which in turn calls
-  `sets.is_equal`.
-  """
+  # Note that if this test fails, the results for the other `sets` tests will
+  # be inconclusive because they use `asserts.set_equals`, which in turn calls
+  # `sets.is_equal`.
   env = unittest.begin(ctx)
 
   asserts.true(env, sets.is_equal([], []))
diff --git a/tests/shell_tests.bzl b/tests/shell_tests.bzl
index 5e8c280..24288a1 100644
--- a/tests/shell_tests.bzl
+++ b/tests/shell_tests.bzl
@@ -85,12 +85,12 @@ def _shell_spawn_e2e_test_impl(ctx):
       "line tab\tcharacter $foo qu\"o\"te it'\\''s foo\\bar back`echo q`uote'",
       '[[ "${output}" == "${expected}" ]]',
   ])
-  ctx.file_action(
+  ctx.actions.write(
       output = ctx.outputs.executable,
       content = script_content,
-      executable = True,
+      is_executable = True,
   )
-  return struct()
+  return []
 
 shell_spawn_e2e_test = rule(
     test = True,