LocalReadOnlyStream must declare itself not writeable

Makes sense!

Fixing title for gender neutrality.

1. +++ b/core/modules/file/tests/src/Kernel/LocalReadOnlyStreamTest.php
   @@ -0,0 +1,25 @@
   +class LocalReadOnlyStreamTest extends KernelTestBase {
   

   why is this a kernel test? No need for a database here, so this can be a unit test, right?

2. +++ b/core/modules/file/tests/src/Kernel/LocalReadOnlyStreamTest.php
   @@ -0,0 +1,25 @@
   +    $this->assertFalse($type & StreamWrapperInterface::WRITE);
   

   assertFalse() is not correct here, since the result of the bitwise AND will be another integer (type mismatch). So this should be assertSame(0, $type & StreamWrapperInterface::WRITE)

Sorry I didnt see the ask in #drupal-contribute, but I ran the testbot locally, and its a pretty classic error. The testbots should be better about this kind of reporting:

Available test groups & classes
-------------------------------

exception 'Drupal\simpletest\Exception\MissingGroupException' with message 'Missing @group annotation in Drupal\Tests\Core\File\LocalReadOnlyStreamTest' in /var/www/html/core/modules/simpletest/src/TestDiscovery.php:351
Stack trace:
#0 /var/www/html/core/modules/simpletest/src/TestDiscovery.php(177): Drupal\simpletest\TestDiscovery::getTestInfo('Drupal\\Tests\\Co...', '/**\n * @coversD...')#1 /var/www/html/core/modules/simpletest/simpletest.module(571): Drupal\simpletest\TestDiscovery->getTestClasses(NULL, Array)
#2 /var/www/html/core/scripts/run-tests.sh(69): simpletest_test_get_all(NULL)
#3 {main}

+++ b/core/tests/Drupal/Tests/Core/File/LocalReadOnlyStreamTest.php
@@ -0,0 +1,24 @@
+    $type = DummyReadOnlyStreamWrapper::getType();
+    // Checks that the stream wrapper type is not declared as writable.
+    $this->assertSame(0, $type & StreamWrapperInterface::WRITE);

Can't we add this assertion to the existing \Drupal\KernelTests\Core\File\ReadOnlyStreamWrapperTest::testReadOnlyBehavior() instead of creating a whole new test class just for a method?

Awesome :)

Committed 7b0d229 and pushed to 8.2.x. Thanks!
Committed 48b3d70 and pushed to 8.1.x. Thanks!