The dynamic GUI is selected on the command line via the “-g” option. Alternatively, it is started by clicking “Run” in the static GUI toolbar.

The initial left window is a tree view of all the tests that are being run. These are colour-coded: white tests have not started yet, yellow tests are currently in progress, green tests are reckoned to have succeeded while red tests are reckoned to have failed. By clicking the rows in this view details of what happened to a particular test can be examined.

Ordinarily, TextTest will run each test in order until all tests have been completed, successfully or otherwise. You can however request that it stops after the first test that fails, by selecting "Stop after first failure" in the static GUI running tab, or "-stop" on the command line.

When whole test suites become complete and all tests in them have succeeded, the dynamic GUI will automatically collapse the tree view for that suite and simply identify that line by the number of tests that were successful. This aids the user in seeing which tests need his attention. If this behaviour is found to be undesirable for any reason, it can be disabled by setting the config file value 'auto_collapse_successful' to 0.

The initial right window is a summary of how many tests are in a given state and is continually updated as they change. When they complete, if they fail they are sorted into categories of which files differed underneath the “Failed”. Note that as several files can differ in the same test this doesn't necessarily add up to the total number of failed tests.

For each file which has differences, subgroups will then appear (labelled Group 1, Group 2 etc.) for tests which have failed with an identical difference in that file. Tests which have a unique diff will not appear in any such group. "Identical" here is configurable: by default the "diff" tool is used and TextTest will only compare using the lines beginning with '<' or '>', filtering out the lines that indicate which line numbers were different. So tests will be grouped together if they gain the same line at different points in the file, for example. This can be configured using the config file dictionary setting "text_diff_program_filters", which is keyed on diff programs and identifies lines from their output that should be preserved in the output.

The status tab also doubles as a way of selecting and hiding whole categories of tests at once. Clicking the lines will select all such tests in the test tree view. Unchecking the check boxes on the right will cause all tests in that category to be hidden in the test tree view on the left. If you uncheck one of the “<file> different” lines, note that tests will only be hidden if all files that were different are marked as hidden, so if a file is different in more than one file it will not be hidden until you uncheck all the files where it was different. In this example there is only one file anyway.

Note that whether categories are visible by default can be configured using the config file list entry “hide_test_category” (a common usage is to hide all successful tests automatically). To refer to the various categories, you can use any name that appears in the status tab, or you can use the keys from for example the “test_colours” entry in the config file table.

When tests are selected via either of the above means, a new “Test” tab is created on the right, containing the details of what's going on in that test. Another tree view, this time of the result files of that test, appears in the top right window, while a textual summary of what happened for this test can be seen in the “Text Info” tab below. The files are also colour-coded, depending on whether TextTest thought they were different (red) or not (green).

Double clicking on files from the test view will bring up views of those files, using the external tools specified in the config file. The relevant entries are "diff_program" for viewing differences, "follow_program" for following a running test and "view_program" for viewing a static file. These default to “tkdiff”, “xterm -e tail -f” and “emacs” respectively on UNIX systems, “tkdiff”, “baretail” and “notepad” on Windows. By default differences will be shown if they are thought to exist (red files) otherwise the file is simply viewed. To select other ways to view the files, right-click and select a viewer from the popup menu.

"follow_program" is used for monitoring the progress of a running test. Ordinarily it is only available from the popup menu, but you can make it come up when double clicking a file in a running test by setting "follow_file_by_default" to 1. When starting this viewer, TextTest will set the environment variable TEXTTEST_FOLLOW_FILE_TITLE to an appropriate name for the window title, which can then be referred to in your "follow_program" setting, as indeed the default setting on UNIX does.

Note the config entries described above are all “composite dictionary” entries and can thus be configured per file type, using just the stems as keys. It is thus easy to plugin custom viewers if particular files produced by the system are more conveniently viewed that way. For example, this will cause the "stdout" files to be viewed with "xemacs" rather than the default "emacs":

[view_program]
stdout:xemacs

On the Text Info tab you will see a textual preview of all the file differences, along with a summary of what happened to the test. This textual preview is also used by the batch mode email report. The tool used to generate the diff can be configured via the config file entry “text_diff_program” (it defaults to “diff”, which is also used internally by “tkdiff”). Each file diff is truncated: the number of lines included can be set via “lines_of_text_difference”, which defaults to 30.

If several files differ they will be displayed in alphabetical order. Sometimes this is not ideal as some files give better information than others. In these cases you should use the config file dictionary setting “failure_display_priority” which will allow you to ensure the most informative file comes at the top. Low numbers imply display first.

To protect from very large files being compared (or viewed), which may result in using all the machine memory, you can specify a maximum file size for this, using the “max_file_size” config file entry. It defaults to "-1" which means no limit. For example:

[max_file_size]
diff:1GB
emacs:500MB

I.e. the keys are the various programs. "default" can be used as normal to set a fallback limit for tools not explicitly listed. If a file exceeds this size for "diff", no diff report will be displayed in the Text Info tab, and if you try and view such a file from the GUI you will get a warning that the file is very large before it will be loaded.

When tests fail, you can examine the differences as above, and sometimes you will decide that the change in behaviour is in fact desirable. In this case, you should “Save” the test, or group of tests. This operation will overwrite the permanent “standard” files with the “temporary” files produced by this run.

To achieve this, the dynamic GUI has a “Save” button in the toolbar and the File menu, and also a “Save As...” action in the File menu. Select the tests you wish to save from the left-hand test window by single-clicking, and using Ctrl+left click to select further tests. (Press Ctrl-A to select all tests) On pressing “Save” (or Ctrl+S), all selected tests will be saved.

On saving a test, by default all files registered as different will be saved. You can however save only some of the files by selecting the files you wish to save from the file view (under the Test tab) in much the way you select multiple tests in the tree view window.

TextTest will normally save the files exactly as the system under test created them, and then perform its filtering on them again before each test run. You can however tell it to save the filtered output as the new standard result, by setting the configuration setting "save_filtered_file_stems". This is mainly useful when

1. the information filtered away isn't interesting and
2. the filtering is much simpler to do on the present run than on an arbitrary one

To enable this for e.g. "stdout" and "myfile", you set

save_filtered_file_stems:stdout
save_filtered_file_stems:myfile

By doing "Save As...", you get a dialog up with further configuration options. You can configure which version the results are saved as (look here for a description of versions). By default, they will be saved as the version that you ran the dynamic GUI as. There is a drop-down list so that you can select other versions if you want to, which will generally include the current version and all versions more general than it. Sometimes you don't want results to be saved for particular versions, this can be configured via the “unsaveable_version” entry which will cause these versions not to appear in the list or be selected as default in future.

You can also specify a version identifier to back up the old results as, for which there is a text field in the "Save As..." dialog. This is particularly useful when your project has made a release and you have a separate version of the tests for that release.

You can also overwrite all the files, even if they were regarded as the same, via the option “replace successfully compared files also”: this is a way to re-generate the run-dependent text for all files in a failing test. Note that this only works on tests where at least some files were different, it won't work on tests that are considered to have succeeded. To systematically regenerate run-dependent text, run with the "--ignorefilters" flag (or check the box in the Advanced tab in the static GUI) which will cause tests to fail and hence make the process of saving run-dependent text much more visible.

There are several occasions on which it can be useful to trigger a recomputation of the test results. Sometimes other versions of the tests are simply saved, which changes files shared between several versions. Sometimes the standard files for the tests are changed externally, via something like a version control update. The filtering settings in the config files might also be changed, and hence a recomputation could be triggered to see if the test now succeeds with the new filtering rules. For these reasons there exists a "Recompute Status" action in the Actions menu.

Each time tests are selected or saved in the dynamic GUI, TextTest will check the file modification times to see if a recomputation seems to be necessary. If it is, a small refresh icon will be shown to the right of that test in the test tree view. It isn't necessary for such an icon to be shown in order to perform "Recompute Status" but in most cases it won't have any effect.

It's also possible to run this action on a test that has not yet completed. In this case it will perform a filtering on the test files produced so far, which gives you the possibility to view them and check if the test is clearly going to fail. It will also attempt to estimate how far the test has progressed, by comparing the size of the standard files to the size of the temporary files produced so far.

Sometimes you have a lot of tests failing for different reasons. It can be helpful to be able to manually classify these tests as you discover what caused individual failures, so that you can see which tests still need to be checked. You can therefore "mark" tests with a particular text, which will cause them to be classified differently and be easy to hide as a group from the Status view. This is achieved by right-clicking on the test and selecting the relevant item from the popup menu.

On the right hand side of the dynamic GUI there is a tab called Run Info. It contains two textual displays. The top half shows information about the TextTest run itself, what arguments were given and when it started etc. The bottom half shows information about the run of the currently selected test(s), including the exact command line and environment it was started with. The purpose is twofold: to aid with identifying different dynamic GUI windows if many runs are started simultaneously on longer-running tests, and to help with debugging if TextTest appears not to be running the system under test in the way you expect.

For especially important longer runs it's possible to provide a name for the run, which is a way of providing a succinct description and a guard against accidental closure at the same time. This is done via View / Set Run Name from the menus in the dynamic GUI. It can also be done externally via "-name" on the command line or via the "Name this Run" field in the Running /Advanced tab in the static GUI.

If the run is named in this way, the window header will be changed, the Run Info updated and when you try to quit a warning dialog will appear to make sure you haven't made a mistake.

There is an environment variable TEXTTEST_DYNAMIC_GUI_INTERPRETER which is a hook to provide additional arguments to Python when starting the dynamic GUI from the static GUI. This is mostly useful for development, for example to plug in a coverage tool or profiler.