Write tests for IEF multiple field widget

This is amazing! I am very excited about this test as it is testing the most important part of this module. I have few comments, but they're mostly of cosmetic nature.

1. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
   @@ -0,0 +1,328 @@
   +    $this->assertFieldByName('multi[form][inline_entity_form][title][0][value]');
   +    $this->assertFieldByName('multi[form][inline_entity_form][first_name][0][value]');
   +    $this->assertFieldByName('multi[form][inline_entity_form][last_name][0][value]');
   +    $this->assertFieldByXpath('//input[@type="submit" and @value="Create node"]', NULL, 'Found "Create node" submit button');
   

   Would be nice to have meaningful messages associated with all asserts.

   Applies to the entire test.

2. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
   @@ -0,0 +1,328 @@
   +    // Now submit 'Add new node' button
   

   Comment should end with a period. Applies to the entire patch.

3. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
   @@ -0,0 +1,328 @@
   +   * Tests if creation of entities works.
   +   * Checks values of created entity.
   +   * Tests if correct fields appear in the table.
   +   * Tests if edit and remove buttons appear.
   

   This comment seems strange. We should have meaningful first line and further explanation below it.

4. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
   @@ -0,0 +1,328 @@
   +    $edit = [];
   

   No need to initialize empty array as we re-initialize it few lines below.

5. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
   @@ -0,0 +1,328 @@
   +    $nodeMulti = $node->get('multi')->getValue();
   +    $this->assertTrue($nodeMulti[0]['target_id'] == $nodeId, 'Refererence node id set to '. $nodeId);
   

   We can probably simplify this to

   $node->multi->target_id == $node->id()
   

6. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
   @@ -0,0 +1,328 @@
   +    $edit = [];
   

   Same as above (no need to init empty array).

7. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
   @@ -0,0 +1,328 @@
   +    $title = $cell[0]->__toString();
   

   I think we shouldn't use __toString() directly. We can simply cast I believe. Applies to the entire patch.

8. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
   @@ -0,0 +1,328 @@
   +    // Delete the third entity reference only, don't delete the node.
   +    // The third entity now is second referenced entity
   +    // because the second one is deleted in previous step.
   

   Let's make lines in comments 80 chars long.

9. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
   @@ -0,0 +1,328 @@
   +      $title = 'Some reference '. $i;
   

   . should have space on both sides. Applies to the entire patch.

10. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
    @@ -0,0 +1,328 @@
    +        'multi[form][entity_id]' => $title .' ('. $referenceNodes[$title] .')',
    

    Is this working as expected? Shouldn't we pass entity ID in the parenthesis?

11. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
    @@ -0,0 +1,328 @@
    +   * @return array Array of created node ids keyed by labels.
    

    Description should be in next line.

12. +++ b/src/Tests/InlineEntityFormMultipleWebTest.php
    @@ -0,0 +1,328 @@
    +  protected function createReferenceContent($numNodes = 3) {
    

    I think it would make sense to create base class for IEF tests and move helper functions in there (createReferenceContent(), setAllowExisting() and getButtonName()).

#8 fixed and chasing rename from multiple to complex.

Committed. @dbolinovski++

Sure. Any improvements to tests are welcome. Feel free to open a new issue for that.

Issues with multiple IEF forms sound like a bug. Should we open a bug report for those too?