Fix tests

* Use Mockery & dataProvider insted of foreach statement

* Delete unnecessary line from testParameterWithHeading()

* Add test to testParameterWithHeading() when user put multiple line to heading
Add PanelPluginTest::testHeadingWithCustomClass
Change how to parse headings for flexible parse.

This commit contain that:

* Resolve PanelPluginTest::testHeadingParse

* Resolve PanelPluginTest::testMultipleHeadingParse

* Resolve PanelPluginTest::testHeadingWithCustomClass
Add some tests to PanelPluginTest and add comment.

* Add PanelPluginTest::testHeadingWithSomeClass

* Add PanelPluginTest::testHeadingWithCustomData

* Add PanelPluginTest::testParseHeadingAndElse

This commit contain some typo fix.
Resolve all PanelPluginTest