Music Example

We'll write the remainder of this page as if it were describing stories for the music library/player. We'll use italics when we want to point out features of the framework. You might as well run the example now before you continue reading.

• http:run.cgi

Browsing Music

The music browser starts up looking at the whole library of songs. We specify the library (an advanced feature) so that we know what we are talking about in this document.

fit.ActionFixture
start	eg.music.Browser
enter	library	Music.txt
check	total songs	37

This is a the file that library reads. It is tab separated text. Try downloading it and looking at it with a spreadsheet. http:Release/Source/eg/music/Music.txt

We can pick songs and see details of our selection as we go.

fit.ActionFixture
enter	select	1
check	title	Akila
check	artist	Toure Kunda
enter	select	2
check	title	American Tango
check	artist	Weather Report
check	album	Mysterious Traveller
check	year	1974
check	time	3.70
check	track	2 of 7

ActionFixture interprets the words in the first column. The actions operate on fields and buttons on the Browser screen we started in the first table. The Browser (or what ever other Fixtures we start) interprets the names in the second column. Each name maps to a method of the Browser. The third column provides data that are pass as arguments to Browser methods or compared with Browser method results. See MusicExampleWithErrors to see how errors are reported.

Playing Music

Once we've picked a song, we can play it. We can continue operating the Brower while music is playing. Since this sequence is long, we'll explain what we are doing in an unused column.

eg.music.Realtime
press	play		play this song
check	status	loading
pause	2
check	status	loading	watch it load
pause	2
check	status	playing
check	playing	American Tango
check	time	3.70
press	pause		make it stop
check	status	pause
check	remaining	3.66
pause	60
check	remaining	3.66
press	play		make it go
check	status	playing
pause	60
check	remaining	2.66
await	play complete		enjoy the music
check	status	ready
enter	select	4	try another
press	play
pause	1
fail	load jam		uh oh
check	message	load jamed
press	ok		dispatch the notifier
check	status	ready

This table is interpreted by Realtime, a Fixture that adds actions having to do with realtime operation of the music player. This fixture calls on a simulator to keep track of system events. We do so here only because the application we are testing isn't a real music player. Our toy application cooperates with the simulator to keep track of time. A real player would do things that take real time and it would use the computer's realtime clock to keep track of time. We could still use a fixture with actions like pause and await but there wouldn't need to be a simulator too.

Searching for Music

There are buttons on the browser to find more songs like the one we have picked.

eg.music.Realtime
enter	select	2	pick an album
press	same album		find more like it
check	status	searching
await	search complete
check	status	ready
check	selected songs	2

Our searches take a few seconds to complete. Eventually we will want to try mashing buttons faster than the computer can respond. For now we will be polite and await completion of our searches.

The selected songs are displayed in a table.

eg.music.Display
title	artist	album	year	time()	track()
Scarlet Woman	Weather Report	Mysterious Traveller	1974	5.72	6 of 7
American Tango	Weather Report	Mysterious Traveller	1974	3.70	2 of 7

Here we use Display (a RowFixture) to directly examine the Music object found by our search. Things like artist and track() are fields and methods of the domain objects.

We can find songs related in different ways. Each new way produces a (possibly) different list of songs. Show all restores the display to the initial conditions.

eg.music.Realtime
press	show all		recall all the songs
await	search complete
check	selected songs	37
enter	select	3	pick a James Taylor song
check	artist	James Taylor
press	same artist		find more by him
await	search complete
check	selected songs	5

Yielding the display:

eg.music.Display
title	artist	album	year	time()	track()
Handy Man	James Taylor	JT	1977	3.30	7 of 12
Sailing To Philadelphia	James Taylor	October Rose	2001	5.47	3 of 3
Ananas	James Taylor	Hourglass	1997	5.73	5 of 13
Another Grey Morning	James Taylor	JT	1977	2.73	4 of 12
Copperline	James Taylor	New Moon Shine	1991	4.37	1 of 12

Domain objects typically have lots more fields and methods than we can conveniently look at in a single table. We compose a table specific to our needs by choosing column headings of interest. Here is another look at the results of the previous search.

eg.music.Display
title	album	genre	size	date
Another Grey Morning	JT	Pop	3284199	9/7/02 11:32 PM
Ananas	Hourglass	Pop	6897450	9/7/02 11:47 PM
Copperline	New Moon Shine	Pop	5248087	9/7/02 9:52 PM
Handy Man	JT	Pop	3976956	9/7/02 11:36 PM
Sailing To Philadelphia	October Rose	Pop	6581911	9/7/02 10:45 PM

Notice that the songs in the two tables are not in the same order. That is because we didn't type the tables in the same order, and the order we type is preserved. RowFixture(s) use the left hand columns to line up the search results with the table values. Check out MusicExampleWithErrors to see how this works when the rows don't match up.

The kaffe jvm/library has trouble with date formatting so you may see errors when running this from wiki.

This completes the MusicExample.

We've run quite a few test. We'll call up one more Fixture that will add a summary to the end of our document.

fit.Summary