Pinyin Trainer from trainchinese tests your ability to distinguish pinyin initials, tones, and/or sequences of two tones. You can choose to be tested on any one of these or a combination of all three. There seems to be no option, however, for testing pinyin finals. So if you need work distinguishing gān from gāng, for example, this app won’t help.
The format is multiple choice, ranging from 2-4 choices for each syllable; there is also an “artist mode” if you want to sketch tone marks.
The app keeps a running tally of right/wrong responses. These are not just numbers, but rather a list of the words tested and what your response was. This is great for finding patterns of errors, for example, if you have trouble distinguishing x from sh, or second tones from third. On an iPad in landscape orientation (as in the image above), this list is constantly visible on the right of the screen. On the iPhone/iPod, the numerical count is constantly displayed and details are available by tapping the “Review” button.
A nice extra is the inclusion of a detailed guide to pinyin and tones (including tone sandhi rules), with audio. At the end there is a chart where you can select an initial and get audio for all syllable and tone combinations beginning with that initial.
There is a daily limit of 25 questions, as well as ads, unless you upgrade through an in-app purchase.