Use KernelTestBase instead of deprecated UnitTestBase.
Merge pull request #18 from fubhy/use-kerneltestbase

Use KernelTestBase instead of deprecated UnitTestBase.
Use wget for downloading Drupal instead of Drush to prevent random test failures when there is a new Drupal development snapshot.
Merge pull request #20 from fubhy/wget-for-travis

Use wget for downloading Drupal instead of Drush to prevent random test fails.
Added basic README contributing info and test execution instructions.
Merge pull request #22 from klausi/readme-2276369

Added basic README contributing info and test execution instructions.
Added action expression.