Manual testing very important as many of the automated tools are not able to detect certain errors such as alternative text that is not meaningful. In these cases a web developer needs to use manual testing to resolve this issues the are many of manual testing techniques that a web developer can use, one of the most simple is human judgement Other types of manual testing include using one or several screen readers and browsers to see how the screen reader would interpret the site in different browsers. A web developer could also use blind and visually impaired users as part of the testing process. All of these options are discussed in more detail below.
It is recommended that a website is tested using a number of browsers and a number of different screen readers. It is also recommended that a page be tested in various browsers with images switched off. If a site is tested using only one screen reader then the web developer needs be aware that most screen readers will react slightly differently when interpreting HTML. For example not all screen readers support the table headers attribute, or the long description attribute for images etc. In order to use a screen reader to fully test a site properly the web developer will need to learn the keystrokes required to operate the screen reader that they using to test the site.
A manual testing method that is not recommended is to unplug the monitor to simulate blindness when testing a website using a screen reader. If the monitor is left on during testing then a web developer can compare the speech output that the screen reader provides with what actually appears on the screen.
If a web developer is going to use a screen reader to these their website then they need to be aware that a fully version of a screen reader costs approximately £500. However there are many demo versions of screen readers that can be downloaded from the Internet free of charge. The screen readers page contains more information about the screen that are available, as well as links to pages where domo versions of certain screen readers can be downloaded free of charge. The screen reader demo’s available are often not full versions of the screen reader software. It is recommended that the web developer check the screen reader demo download page before downloading a demo.
When assessing a web page for accessibility to blind and visually impaired user it is vital that a web developer uses there human judgement, as automated testing tools cannot find all of the inaccessible features on a website. If a web developer is using a screen reader to test a website then they will need to use there human judgement to decide whether or not the speech output provided by the screen reader could be easily understood by a blind or visually impaired user. In some cases web developers may need to test this using blind and visually impaired users to get some realistic feedback. The using blind and visually impaired users page contains information about using blind and visually impaired users to test a website.
A brief list is given below of the things that require a web developer to use there human judgement in order to assess whether or not that particular element of a web page is accessible to a blind or visually impaired user. Some of these things can be assessed by the quality of speech output provided by a screen reader, e.g. are tables accessible. While others rely completely on human judgement e.g. can a user easily distinguish between foreground and background information.