Improve assertNoFieldByName() compatibility for empty strings

Let's also make the docs for assertNoFieldByName() accurate in this issue.

+++ b/core/tests/Drupal/FunctionalTests/AssertLegacyTrait.php
@@ -241,7 +241,7 @@ protected function assertFieldByName($name, $value = NULL) {
-  protected function assertNoFieldByName($name, $value = NULL) {
+  protected function assertNoFieldByName($name, $value = '') {
     $this->assertSession()->fieldNotExists($name);
     if ($value !== NULL) {
       $this->assertSession()->fieldValueNotEquals($name, (string) $value);

shouldn't you also change the if() condition to check for the new default value?

Can you expand the test in BrowserTestBaseTest::testLegacyXPathAsserts() to cover this?

1. +++ b/core/tests/Drupal/FunctionalTests/AssertLegacyTrait.php
   @@ -228,22 +228,22 @@ protected function assertFieldByName($name, $value = NULL) {
   -   * Asserts that a field exists with the given name and value.
   +   * Asserts that a field don't exist with the given name and value.
   

   should be "doesn't"

2. +++ b/core/tests/Drupal/FunctionalTests/AssertLegacyTrait.php
   @@ -228,22 +228,22 @@ protected function assertFieldByName($name, $value = NULL) {
   -   *   (optional) Value of the field to assert. You may pass in NULL (default)
   +   *   (optional) Assert field not equal to the Value. You may pass in NULL (default)
       *   to skip checking the actual value, while still checking that the field
   -   *   exists.
   +   *   don't exist.
   

   Should be "(optional) Value of the field, to assert that the field's value on the page does not match it."

   from the original method in Simpletest.

And we still need to expand the test cases as I said above.

Very good, just a tiny thing:

+++ b/core/tests/Drupal/FunctionalTests/BrowserTestBaseTest.php
@@ -2,6 +2,7 @@
@@ -163,6 +164,19 @@ public function testLegacyXPathAsserts() {

@@ -163,6 +164,19 @@ public function testLegacyXPathAsserts() {
 
     $this->assertNoFieldByXPath('//notexisting');
     $this->assertNoFieldByXPath("//input[@id = 'edit-name']", 'wrong value');
+
+    $this->assertNoFieldByName('name');

ah, sorry, this test method is about legacy xpath asserts ...

We can just rename the test method to testLegacyFieldAsserts() since all methods tested have "field" in their name :)

I think we can cover flaws in assertNoFieldById() in another issue.

Looks good, thanks!