Improve "update" command; add test

tests/commands/test_update.py

@@ -0,0 +1,29 @@
+# Copyright 2014-present Ivan Kravets <me@ikravets.com>
+#
+# 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 platformio.commands.update import cli as cmd_update
+
+
+def test_update(platformio_setup, clirunner, validate_cliresult):
+    matches = (
+        "Platform Manager",
+        "Up-to-date",
+        "Library Manager"
+    )
+    result = clirunner.invoke(cmd_update, ["--only-check"])
+    validate_cliresult(result)
+    assert all([m in result.output for m in matches])
+    result = clirunner.invoke(cmd_update)
+    validate_cliresult(result)
+    assert all([m in result.output for m in matches])