Add a test for exporting Futures (#2447)

It should be possible to export Futures as stack outputs - this test
ensures that this is the case.

sdk/python/lib/test/langhost/outputs_future/__init__.py

@@ -0,0 +1,13 @@
+# Copyright 2016-2019, Pulumi Corporation.
+#
+# 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.

sdk/python/lib/test/langhost/outputs_future/__main__.py

@@ -0,0 +1,21 @@
+# Copyright 2016-2018, Pulumi Corporation.
+#
+# 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.
+import pulumi
+from pulumi.runtime import invoke
+
+async def do_invoke():
+    value = await invoke("test:index:MyFunction", props={"value": 41})
+    return value["value"]
+
+pulumi.export("value", do_invoke())

sdk/python/lib/test/langhost/outputs_future/test_outputs_future.py

@@ -0,0 +1,38 @@
+# Copyright 2016-2018, Pulumi Corporation.
+#
+# 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.
+from os import path
+from ..util import LanghostTest
+
+
+class TestOutputsFuture(LanghostTest):
+    def test_outputs_future(self):
+        self.run_test(
+            program=path.join(self.base_path(), "outputs_future"),
+            expected_resource_count=0)
+
+    def invoke(self, _ctx, token, args, _provider):
+        self.assertEqual("test:index:MyFunction", token)
+        self.assertDictEqual({
+            "value": 41,
+        }, args)
+
+        return [], {
+            "value": args["value"] + 1
+        }
+
+    def register_resource_outputs(self, _ctx, _dry_run, _urn, ty, _name, _resource, outputs):
+        self.assertEqual(ty, "pulumi:pulumi:Stack")
+        self.assertDictEqual({
+            "value": 42
+        }, outputs)