# Original PR description:
On Cocoapods version 1.6.0 beta 2 we get an error on pod install because certain test targets don't have any sources to compile. This PR adds some skeleton unit test source files to get that working. Is everyone okay with these (for now) basically empty files?
Closes#5825
# FInal PR description:
The original aim of this PR was to get the project working with the Cocoapods 1.6 beta.
I initially didn't know where to begin getting it to work, so I used `pod lib lint` to get answers. `pod lib lint` had issues with the following things:
1. test_specs not having any sources to compile. This was due to our pattern of putting unit test test_specs inside of parent test_specs that didn't have anything else.
To address this I did two things. First, I moved away from the nested test_spec pattern. Now, instead of "Subspec/tests/unit_tests" it's "Subspec/UnitTests". This is more in line with the style Cocoapods uses [here](http://blog.cocoapods.org/CocoaPods-1.6.0-beta/). Secondly, I added some dummy files for things like UIMetrics and MaterialMath.
2. Importing headers across modules without using framework style imports.
I added framework style imports. This required some additional rewrite rules in the kokoro script.
3. Dependencies across subspecs being implicit.
I made them explicit by adding dependency statements to the podspecs where needed.
`pod lib lint` didn't take issue with this, but I also saw that `MaterialComponents` was depending on `MaterialComponentsBeta` in various places. For example, all the theming extensions were in beta, but the tests for them weren't. I moved the tests to test_specs within the beta extensions. This required some directory structure changes. These changes then required some BUILD file changes. Making BUILD file changes made me realize that some swift unit tests weren't being accounted for by bazel. I took care of this too.
This PR also fixes some swift debugging stuff--"po" statements that weren't working before now do. I didn't rigorously verify this, but I also think this PR will lead to faster clean build times? It kinda seemed like it was while I was working on it.
This change makes use of MDCContainerScheme to provide a single theming-related API for ButtonBar.
Includes example updates unit tests.
This change is the first in a series of changes that will be required to add Theming extension support to AppBar:
- [x] ButtonBar
- [ ] NavigationBar
- [ ] HeaderStackView
- [ ] FlexibleHeader
- [ ] AppBar
Removes the need to copy-paste stanzas from other files anymore as we'll rely on #4478 to generate the correct stanza for us instead.
This was an automated change generated by running a find-and-replace regular expression:
```
/\*
Copyright ([0-9]+)-present the Material Components for iOS 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\.
\*/
```
```
/\*
Copyright ([0-9]+)-present the Material Components for iOS 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\.
\*/
```
```
/\*
Copyright ([0-9]+)-present the Material Components for iOS 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\.
\*/
```
```
// Copyright $1-present the Material Components for iOS 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.
```
* [ButtonBar] Refactor ButtonBarBuilder for testing
Pulling out part of the ButtonBarBuilder logic to start making it more
testable. Extracting the initial configuration of MDCButton from a
UIBarButtonItem into a class method and adding unit tests.
