assertUrlInboundAlter example

$uid = $account->id();
    $name = $account->getAccountName();

    // Test a single altered path.     $this->drupalGet("user/$name");
    $this->assertSession()->statusCodeEquals(200);
    $this->assertUrlOutboundAlter("/user/$uid", "/user/$name");

    // Test that a path always uses its alias.     $this->createPathAlias("/user/$uid/test1", '/alias/test1');
    $this->rebuildContainer();
    $this->assertUrlInboundAlter('/alias/test1', "/user/$uid/test1");
    $this->assertUrlOutboundAlter("/user/$uid/test1", '/alias/test1');

    // Test adding an alias via the UI.     $edit = ['path[0][value]' => "/user/$uid/edit", 'alias[0][value]' => '/alias/test2'];
    $this->drupalGet('admin/config/search/path/add');
    $this->submitForm($edit, 'Save');
    $this->assertSession()->pageTextContains('The alias has been saved.');
    $this->drupalGet('alias/test2');
    $this->assertSession()->statusCodeEquals(200);
    $this->assertUrlOutboundAlter("/user/$uid/edit", '/alias/test2');