housekeeping: factor out components for easier BaseLayout reuse (#4604)

* improve: wrap schemes to encapsulate rendering logic
* improve: wrap filter to encapsulate rendering logic
* improve: wrap info section to encapsulate rendering logic
* improve: wrap servers plugin to encapsulate rendering logic
* improve: added tests for schemes-wrapper rendering logic
* improve: added tests for info-wrapper rendering logic, also do not render info if info is undefined
* improve: added tests for filter rendering logic
* improve: added tests for servers-wrapper rendering logic
* `InfoWrapper` -> `InfoContainer`
* add `containers` alias to Babel configuration
* `SchemesWrapper` -> `SchemesContainer`
* drop `container` from container file names
* `ServersWrapper` -> `ServersContainer`
* `Filter` -> `FilterContainer`
* follow `core/containers` pattern in BasePreset

test/components/info-wrapper.js

@@ -0,0 +1,67 @@
+
+/* eslint-env mocha */
+import React from "react"
+import expect from "expect"
+import { mount } from "enzyme"
+import { fromJS } from "immutable"
+import InfoContainer from "containers/info"
+
+describe("<InfoContainer/>", function () {
+
+  const components = {
+    info: () => <span className="mocked-info"/>
+  }
+  const mockedProps = {
+    specSelectors: {
+      info () {},
+      url () {},
+      basePath () {},
+      host () {},
+      externalDocs () {}
+    },
+    getComponent: c => components[c]
+  }
+
+  it("renders Info inside InfoContainer if info is provided", function () {
+
+    // Given
+    let props = {...mockedProps}
+    props.specSelectors = {...mockedProps.specSelectors}
+    props.specSelectors.info = function () {return fromJS(["info1", "info2"])}
+
+    // When
+    let wrapper = mount(<InfoContainer {...props}/>)
+
+    // Then
+    const renderedInfo = wrapper.find("span.mocked-info")
+    expect(renderedInfo.length).toEqual(1)
+  })
+
+  it("does not render Info inside InfoContainer if no info is provided", function () {
+
+    // Given
+    let props = {...mockedProps}
+    props.specSelectors = {...mockedProps.specSelectors}
+    props.specSelectors.info = function () {return fromJS([])}
+
+    // When
+    let wrapper = mount(<InfoContainer {...props}/>)
+
+    // Then
+    const renderedInfo = wrapper.find("span.mocked-info")
+    expect(renderedInfo.length).toEqual(0)
+  })
+
+  it("does not render Info inside InfoContainer if info is undefined", function () {
+
+    // Given
+    let props = {...mockedProps}
+
+    // When
+    let wrapper = mount(<InfoContainer {...props}/>)
+
+    // Then
+    const renderedInfo = wrapper.find("span.mocked-info")
+    expect(renderedInfo.length).toEqual(0)
+  })
+})