Remove incorrect test_post_thumbnails_types_true() test

[SergeyBiryukov]

Some history on add_theme_support( 'post-thumbnails' ):

• Introduced as post-images in [12350] / #11364.
• Renamed to post-thumbnails in [12351].
• Some unit tests added in [435/tests].
• Some incorrect tests removed in [30148] / #18548.
• Merging of supported post types added in [37308] / #22080.

In hindsight, some tests added in [435/tests] were incorrect, as the types argument was never supported:

add_theme_support( 'post-thumbnails', array( 'types' => array( 'post', 'page' ) ) );

This is the correct syntax instead:

add_theme_support( 'post-thumbnails', array( 'post', 'page' ) );

Some tests were removed in [30148] / #18548. test_post_thumbnails_types_true() was left as is at the time, because it passed. The test ensures that adding post-thumbnails support for array( 'types' => true ) results in thumbnails being supported for any post type:

add_theme_support( 'post-thumbnails', array( 'types' => true ) );
$this->assertTrue( current_theme_supports( 'post-thumbnails' ) );
$this->assertTrue( current_theme_supports( 'post-thumbnails', rand_str() ) );

However, that is an incorrect assumption. Thumbnail support for any type is only achieved by omitting the array altogether. This is already tested in test_post_thumbnails_mixed_args() a few lines above:

add_theme_support( 'post-thumbnails' );
$this->assertTrue( current_theme_supports( 'post-thumbnails', 'book' ) );

and does not need an additional test.

test_post_thumbnails_types_true() boils down to this check in current_theme_supports():

in_array( rand_str(), array( 'types' => true ) )

It only passes by accident due to fact that this always returns true without a strict type check.

Discovered while working on switching to strict in_array() checks across core in #49542.

[SergeyBiryukov]

In 47548:

Tests: Remove test_post_thumbnails_types_true().

The test incorrectly describes the behavior of current_theme_supports( 'post-thumbnails' ) and only passes by accident.

Follow-up to [30148].

Fixes #49801.