Modernize & harden HalLinkManagerTest

This looks great for me! We could try to share code between the two providers, but I actually believe that DRY for tests is totally overstated.

+++ b/core/modules/hal/tests/src/Kernel/HalLinkManagerTest.php
@@ -46,36 +46,123 @@ protected function setUp() {
+        'link_domain' => 'http://llamas-rock.com/for-real/',

I was disappointed to find this site does not actually exist. Quick, grab the domain! :P

+++ b/core/modules/hal/tests/src/Kernel/HalLinkManagerTest.php
@@ -46,36 +46,123 @@ protected function setUp() {
+  public function providerTestGetTypeUri() {

Don't these need phpdoc? If they don't is that in coding standards somewhere?

There are glorious examples like:

 /**
   * {@inheritdoc}
   */
  public function providerSource() {

over

  /**
   * Data provider for testPurge().
   *
   * @see testPurge()
   */

to

  /**
   * Provides test data for testApplies().
   *
   * @return array
   *   Array of datasets for testApplies(). Structured as such:
   *   - ForumListBreadcrumbBuilder::applies() expected result.
   *   - ForumListBreadcrumbBuilder::applies() $attributes input array.
   */

I always assumed the only standard was just some kind of naming scheme.

I agree with @Wim Leers and @dawehner - the most important thing in the data provider is the text in the array keys - makes it so much easier to work out what's going on.

I do think that

+++ b/core/modules/hal/tests/src/Kernel/HalLinkManagerTest.php
@@ -46,36 +46,123 @@ protected function setUp() {
   /**
    * @covers ::getRelationUri
+   * @dataProvider providerTestGetRelationUri
    */
-  public function testGetRelationUri() {
+  public function testGetRelationUri($link_domain, $entity_type, $bundle, $field_name, array $context, $expected_return, array $expected_context) {

We're going to have a problem when we turn on the rule for @param documentation. I think it might be worth considering coding standards for tests. In some ways it is tempting to say it should be just the same as for regular code. So we don't have to maintain multiple rulesets. I dunno.

I've pinged @catch for more opinion.

@Wim Leers - good idea I'll propose a coding standards change in their issue queue.

Created #2918440: Define a standard for documenting data providers in PHPUnit-based tests.

Discussed with @catch and he said:

the data provider I just didn’t want us getting tripped up by coding standards checks, that was it.

Committed and pushed ff6381f7cf to 8.5.x and 94f54936f6 to 8.4.x. Thanks!

Backported to 8.4,x because it is a test only change.