class ConfigFormOverrideTest

class ConfigFormOverrideTest extends BrowserTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * Tests that overrides do not affect forms.
     */
    public function testFormsWithOverrides() {
        $this->drupalLogin($this->drupalCreateUser([
            'access administration pages',
            'administer site configuration',
        ]));
        $overridden_name = 'Site name global conf override';
        // Set up an override.
        $settings['config']['system.site']['name'] = (object) [
            'value' => $overridden_name,
            'required' => TRUE,
        ];
        $this->writeSettings($settings);
        // Test that everything on the form is the same, but that the override
        // worked for the actual site name.
        $this->drupalGet('admin/config/system/site-information');
        $this->assertSession()
            ->titleEquals('Basic site settings | ' . $overridden_name);
        $this->assertSession()
            ->fieldValueEquals("site_name", 'Drupal');
        // Submit the form and ensure the site name is not changed.
        $edit = [
            'site_name' => 'Custom site name',
        ];
        $this->drupalGet('admin/config/system/site-information');
        $this->submitForm($edit, 'Save configuration');
        $this->assertSession()
            ->titleEquals('Basic site settings | ' . $overridden_name);
        $this->assertSession()
            ->fieldValueEquals("site_name", $edit['site_name']);
    }

}