The Common Test framework provides a high-level operator interface for testing, providing the following features:

When Common Test starts, it automatically attempts to compile any suites included in the specified tests. If particular suites are specified, only those suites are compiled. If a particular test object directory is specified (meaning all suites in this directory are to be part of the test), Common Test runs function make:all/1 in the directory to compile the suites.

If compilation fails for one or more suites, the compilation errors are printed to tty and the operator is asked if the test run is to proceed without the missing suites, or be aborted. If the operator chooses to proceed, the tests having missing suites are noted in the HTML log. If Common Test is unable to prompt the user after compilation failure (if Common Test does not control stdin), the test run proceeds automatically without the missing suites. This behavior can however be modified with the flag , or the ct:run_test/1 option . If is set to true, the test run stops immediately if some suites fail to compile.

Any help module (that is, regular Erlang module with name not ending with "_SUITE") that resides in the same test object directory as a suite, which is part of the test, is also automatically compiled. A help module is not mistaken for a test suite (unless it has a "_SUITE" name). All help modules in a particular test object directory are compiled, no matter if all or only particular suites in the directory are part of the test.

If test suites or help modules include header files stored in other locations than the test directory, these include directories can be specified by using flag with ct_run, or option with . Also, an include path can be specified with an OS environment variable, .

Example (bash):

$ export CT_INCLUDE_PATH=~testuser/common_suite_files/include:~testuser/common_lib_files/include

Common Test passes all include directories (specified either with flag/option , or variable , or both, to the compiler.

Include directories can also be specified in test specifications, see Test Specifications.

If the user wants to run all test suites for a test object (or an OTP application) by specifying only the top directory (for example, with start flag/option dir), Common Test primarily looks for test suite modules in a subdirectory named test. If this subdirectory does not exist, the specified top directory is assumed to be the test directory, and test suites are read from there instead.

To disable the automatic compilation feature, use flag with , or option with . With automatic compilation disabled, the user is responsible for compiling the test suite modules (and any help modules) before the test run. If the modules cannot be loaded from the local file system during startup of Common Test, the user must preload the modules before starting the test. Common Test only verifies that the specified test suites exist (that is, that they are, or can be, loaded). This is useful, for example, if the test suites are transferred and loaded as binaries through RPC from a remote node.

The ct_run program can be used for running tests from the OS command line, for example, as follows:

Examples:

 $ ct_run -config $CFGS/sys1.cfg $CFGS/sys2.cfg -dir $SYS1_TEST $SYS2_TEST
 $ ct_run -userconfig ct_config_xml $CFGS/sys1.xml $CFGS/sys2.xml -dir $SYS1_TEST $SYS2_TEST
 $ ct_run -suite $SYS1_TEST/setup_SUITE $SYS2_TEST/config_SUITE
 $ ct_run -suite $SYS1_TEST/setup_SUITE -case start stop
 $ ct_run -suite $SYS1_TEST/setup_SUITE -group installation -case start stop

The flags dir, suite, and group/case can be combined. For example, to run x_SUITE and y_SUITE in directory testdir, as follows:

 $ ct_run -dir ./testdir -suite x_SUITE y_SUITE

This has the same effect as the following:

 $ ct_run -suite ./testdir/x_SUITE ./testdir/y_SUITE

For details, see Test Case Group Execution.

The following flags can also be used with ct_run:

The ct_run program sets the exit status before shutting down. The following values are defined:

If auto-skipped test cases do not affect the exit status. The default behavior can be changed using start flag:

 -exit_status ignore_config

For more information about the ct_run program, see module ct_run and section Installation.

Common Test provides an Erlang API for running tests. The main (and most flexible) function for specifying and executing tests is ct:run_test/1. It takes the same start parameters as ct_run, but the flags are instead specified as options in a list of key-value tuples. For example, a test specified with ct_run as follows:

$ ct_run -suite ./my_SUITE -logdir ./results

is with ct:run_test/1 specified as:

1> ct:run_test([{suite,"./my_SUITE"},{logdir,"./results"}]).

The function returns the test result, represented by the tuple {Ok,Failed,{UserSkipped,AutoSkipped}}, where each element is an integer. If test execution fails, the function returns the tuple {error,Reason}, where the term Reason explains the failure.

The default start option {dir,Cwd} (to run all suites in the current working directory) is used if the function is called with an empty list of options.

For details, see ct:run_test/1 manual page.

With the ct_run flag, or ct:run_test/1 option group, one or more test case groups can be specified, optionally in combination with specific test cases. The syntax for specifying groups on the command line is as follows:

  [-case ]]]>

The syntax in the Erlang shell is as follows:

  ct:run_test([{group,GroupsNamesOrPaths}, {case,Cases}]).]]>

Parameter group_names_or_paths specifies one or more group names and/or one or more group paths. At startup, Common Test searches for matching groups in the group definitions tree (that is, the list returned from Suite:groups/0; for details, see section Test Case Groups.

Given a group name, say g, Common Test searches for all paths leading to g. By path is meant a sequence of nested groups, which must be followed to get from the top-level group to g. To execute the test cases in group g, Common Test must call the init_per_group/2 function for each group in the path to g, and all corresponding end_per_group/2 functions afterwards. This is because the configuration of a test case in g (and its Config input data) depends on init_per_testcase(TestCase, Config) and its return value, which in turn depends on init_per_group(g, Config) and its return value, which in turn depends on init_per_group/2 of the group above g, and so on, all the way up to the top-level group.

This means that if there is more than one way to locate a group (and its test cases) in a path, the result of the group search operation is a number of tests, all of which are to be performed. Common Test interprets a group specification that consists of a single name as follows:

"Search and find all paths in the group definitions tree that lead to the specified group and, for each path, create a test that does the following, in order:

The user can specify a specific group path with parameter group_names_or_paths. With this type of specification execution of unwanted groups (in otherwise matching paths), and/or the execution of subgroups can be avoided. The command line syntax of the group path is a list of group names in the path, for example:

$ ct_run -suite "./x_SUITE" -group [g1,g3,g4] -case tc1 tc5

The syntax in the Erlang shell is as follows (requires a list within the groups list):

1> ct:run_test([{suite,"./x_SUITE"}, {group,[[g1,g3,g4]]}, {testcase,[tc1,tc5]}]).

The last group in the specified path is the terminating group in the test, that is, no subgroups following this group are executed. In the previous example, g4 is the terminating group. Hence, Common Test executes a test that calls all init configuration functions in the path to g4, that is, g1..g3..g4. It then calls test cases tc1 and tc5 in g4, and finally all end configuration functions in order g4..g3..g1.

Examples:

 -module(x_SUITE).
 ...
 %% The group definitions:      
 groups() ->
   [{top1,[],[tc11,tc12,
	      {sub11,[],[tc12,tc13]},
	      {sub12,[],[tc14,tc15,
			 {sub121,[],[tc12,tc16]}]}]},

    {top2,[],[{group,sub21},{group,sub22}]},
    {sub21,[],[tc21,{group,sub2X2}]},
    {sub22,[],[{group,sub221},tc21,tc22,{group,sub2X2}]},
    {sub221,[],[tc21,tc23]},
    {sub2X2,[],[tc21,tc24]}].

The following executes two tests, one for all cases and all subgroups under top1, and one for all under top2:

 $ ct_run -suite "x_SUITE" -group all
 1> ct:run_test([{suite,"x_SUITE"}, {group,all}]).

Using -group top1 top2, or {group,[top1,top2]} gives the same result.

The following executes one test for all cases and subgroups under top1:

 $ ct_run -suite "x_SUITE" -group top1
 1> ct:run_test([{suite,"x_SUITE"}, {group,[top1]}]).

The following runs a test executing tc12 in top1 and any subgroup under top1 where it can be found (sub11 and sub121):

 $ ct_run -suite "x_SUITE" -group top1 -case tc12
 1> ct:run_test([{suite,"x_SUITE"}, {group,[top1]}, {testcase,[tc12]}]).

The following executes tc12 only in group top1:

 $ ct_run -suite "x_SUITE" -group [top1] -case tc12
 1> ct:run_test([{suite,"x_SUITE"}, {group,[[top1]]}, {testcase,[tc12]}]).

The following searches top1 and all its subgroups for tc16 resulting in that this test case executes in group sub121:

 $ ct_run -suite "x_SUITE" -group top1 -case tc16
 1> ct:run_test([{suite,"x_SUITE"}, {group,[top1]}, {testcase,[tc16]}]).

Using the specific path -group [sub121] or {group,[[sub121]]} gives the same result in this example.

The following executes two tests, one including all cases and subgroups under sub12, and one with only the test cases in sub12:

 $ ct_run -suite "x_SUITE" -group sub12 [sub12]
 1> ct:run_test([{suite,"x_SUITE"}, {group,[sub12,[sub12]]}]).

In the following example, Common Test finds and executes two tests, one for the path from top2 to sub2X2 through sub21, and one from top2 to sub2X2 through sub22:

 $ ct_run -suite "x_SUITE" -group sub2X2
 1> ct:run_test([{suite,"x_SUITE"}, {group,[sub2X2]}]).

In the following example, by specifying the unique path top2 -> sub21 -> sub2X2, only one test is executed. The second possible path, from top2 to sub2X2 (from the former example) is discarded:

 $ ct_run -suite "x_SUITE" -group [sub21,sub2X2]
 1> ct:run_test([{suite,"x_SUITE"}, {group,[[sub21,sub2X2]]}]).

The following executes only the test cases for sub22 and in reverse order compared to the group definition:

 $ ct_run -suite "x_SUITE" -group [sub22] -case tc22 tc21
 1> ct:run_test([{suite,"x_SUITE"}, {group,[[sub22]]}, {testcase,[tc22,tc21]}]).

If a test case belonging to a group (according to the group definition) is executed without a group specification, that is, simply by (using the command line):

$ ct_run -suite "my_SUITE" -case my_tc

or (using the Erlang shell):

1> ct:run_test([{suite,"my_SUITE"}, {testcase,my_tc}]).

then Common Test ignores the group definition and executes the test case in the scope of the test suite only (no group configuration functions are called).

The group specification feature, as presented in this section, can also be used in Test Specifications (with some extra features added).

You can start Common Test in an interactive shell mode where no automatic testing is performed. Instead, Common Test starts its utility processes, installs configuration data (if any), and waits for the user to call functions (typically test case support functions) from the Erlang shell.

The shell mode is useful, for example, for debugging test suites, analyzing and debugging the SUT during "simulated" test case execution, and trying out various operations during test suite development.

To start the interactive shell mode, start an Erlang shell manually and call ct:install/1 to install any configuration data you might need (use [] as argument otherwise). Then call ct:start_interactive/0 to start Common Test.

If you use the ct_run program, you can start the Erlang shell and Common Test in one go by using the flag -shell and, optionally, flag -config and/or -userconfig.

Examples:

If no configuration file is specified with command ct_run, a warning is displayed. If Common Test has been run from the same directory earlier, the same configuration file(s) are used again. If Common Test has not been run from this directory before, no configuration files are available.

If any functions using "required configuration data" (for example, functions ct_telnet or ct_ftp) are to be called from the Erlang shell, first require configuration data with ct:require/1,2. This is equivalent to a require statement in the Test Suite Information Function or in the Test Case Information Function.

Example:

 
 1> ct:require(unix_telnet, unix).
 ok
 2> ct_telnet:open(unix_telnet).
 {ok,<0.105.0>}
 4> ct_telnet:cmd(unix_telnet, "ls .").
 {ok,["ls .","file1  ...",...]}

Everything that Common Test normally prints in the test case logs, are in the interactive mode written to a log named ctlog.html in directory ]]>. A link to this file is available in the file named last_interactive.html in the directory from which you execute ct_run. Specifying a different root directory for the logs than the current working directory is not supported.

If you wish to exit the interactive mode (for example, to start an automated test run with ct:run_test/1), call function ct:stop_interactive/0. This shuts down the running ct application. Associations between configuration names and data created with require are consequently deleted. Function ct:start_interactive/0 takes you back into interactive mode, but the previous state is not restored.

Using ct_run -step [opts], or by passing option {step,Opts} to ct:run_test/1, the following is possible:

If no extra options are specified with flag/option step, breakpoints are set automatically on the test cases that are to be executed by Common Test, and those functions only. If step option config is specified, breakpoints are also initially set on the configuration functions in the suite, that is, init_per_suite/1, end_per_suite/1, init_per_group/2, end_per_group/2, init_per_testcase/2 and end_per_testcase/2.

Common Test enables the Debugger auto-attach feature, which means that for every new interpreted test case function that starts to execute, a new trace window automatically pops up (as each test case executes on a dedicated Erlang process). Whenever a new test case starts, Common Test attempts to close the inactive trace window of the previous test case. However, if you prefer Common Test to leave inactive trace windows, use option keep_inactive.

The step functionality can be used together with flag/option suite and suite + case/testcase, but not together with dir.

The web-based GUI, Virtual Test Server (VTS), is started with the ct_run program. From the GUI, you can load configuration files and select directories, suites, and cases to run. You can also state the configuration files, directories, suites, and cases on the command line when starting the web-based GUI.

Examples:

From the GUI you can run tests and view the result and the logs.

ct_run -vts tries to open the Common Test start page in an existing web browser window, or start the browser if it is not running. Which browser to start can be specified with the browser start command option:

]]>

Example:

If no specific browser start command is specified, Firefox is the default browser on Unix platforms, and Internet Explorer on Windows. If Common Test fails to start a browser automatically, or none is specified as the value for -browser (that is, -browser none), start your favourite browser manually and type the URL that Common Test displays in the shell.

As the execution of the test suites proceed, events are logged in the following four different ways:

Typically the operator, possibly running hundreds or thousands of test cases, does not want to fill the console with details about, or printouts from, specific test cases. By default, the operator only sees the following:

To dig deeper into the general results, or the result of a specific test case, the operator can do so by following the links in the HTML presentation and read the major or minor log files. The "all_runs.html" page is a good starting point. It is located in logdir and contains a link to each test run, including a quick overview (with date and time, node name, number of tests, test names, and test result totals).

An "index.html" page is written for each test run (that is, stored in the ct_run directory tagged with node name, date, and time). This file provides an overview of all individual tests performed in the same test run. The test names follow the following convention:

The "test run index" page includes a link to the Common Test Framework Log file in which information about imported configuration data and general test progress is written. This log file is useful to get snapshot information about the test run during execution. It can also be helpful when analyzing test results or debugging test suites.

The "test run index" page indicates if a test has missing suites (that is, suites that Common Test failed to compile). Names of the missing suites can be found in the Common Test Framework Log file.

The major log file shows a detailed report of the test run. It includes test suite and test case names, execution time, the exact reason for failures, and so on. The information is available in both a file with textual and with HTML representation. The HTML file shows a summary that gives a good overview of the test run. It also has links to each individual test case log file for quick viewing with an HTML browser.

The minor log files contain full details of every single test case, each in a separate file. This way, it is straightforward to compare the latest results to that of previous test runs, even if the set of test cases changes. If application SASL is running, its logs are also printed to the current minor log file by the cth_log_redirect built-in hook.

The full name of the minor log file (that is, the name of the file including the absolute directory path) can be read during execution of the test case. It comes as value in tuple {tc_logfile,LogFileName} in the Config list (which means it can also be read by a pre- or post Common Test Hook function). Also, at the start of a test case, this data is sent with an event to any installed event handler. For details, see section Event Handling.

The log files are written continuously during a test run and links are always created initially when a test starts. Thevtest progress can therefore be followed simply by refreshing pages in the HTML browser. Statistics totals are not presented until a test is complete however.

Common Test uses an HTML Style Sheet (CSS file) to control the look of the HTML log files generated during test runs. If the log files are not displayed correctly in the browser of your choice, or you prefer a more primitive ("pre Common Test v1.6") look of the logs, use the start flag/option:

 basic_html

This disables the use of style sheets and JavaScripts (see Sorting HTML Table Columns).

Common Test includes an optional feature to allow user HTML style sheets for customizing printouts. The functions in ct that print to a test case HTML log file (log/3 and pal/3) accept Category as first argument. With this argument a category can be specified that can be mapped to a selector in a CSS definition. This is useful, especially for coloring text differently depending on the type of (or reason for) the printout. Say you want one color for test system configuration information, a different one for test system state information, and finally one for errors detected by the test case functions. The corresponding style sheet can look as follows:

 div.sys_config  { background:blue; color:white }
 div.sys_state   { background:yellow; color:black }
 div.error       { background:red; color:white }

To install the CSS file (Common Test inlines the definition in the HTML code), the name can be provided when executing ct_run.

Example:

 $ ct_run -dir $TEST/prog -stylesheet $TEST/styles/test_categories.css

Categories in a CSS file installed with flag -stylesheet are on a global test level in the sense that they can be used in any suite that is part of the test run.

Style sheets can also be installed on a per suite and per test case basis.

Example:

 -module(my_SUITE).
 ...
 suite() -> [..., {stylesheet,"suite_categories.css"}, ...].
 ...
 my_testcase(_) ->
     ...
     ct:log(sys_config, "Test node version: ~p", [VersionInfo]),
     ...
     ct:log(sys_state, "Connections: ~p", [ConnectionInfo]),
     ...
     ct:pal(error, "Error ~p detected! Info: ~p", [SomeFault,ErrorInfo]),
     ct:fail(SomeFault).

If the style sheet is installed as in this example, the categories are private to the suite in question. They can be used by all test cases in the suite, but cannot be used by other suites. A suite private style sheet, if specified, is used in favor of a global style sheet (one specified with flag -stylesheet). A stylesheet tuple (as returned by suite/0 above) can also be returned from a test case information function. In this case the categories specified in the style sheet can only be used in that particular test case. A test case private style sheet is used in favor of a suite or global level style sheet.

In a tuple {stylesheet,CSSFile}, if CSSFile is specified with a path, for example, "$TEST/styles/categories.css", this full name is used to locate the file. However, if only the file name is specified, for example, categories.css, the CSS file is assumed to be located in the data directory, data_dir, of the suite. The latter use is recommended, as it is portable compared to hard coding path names in the suite.

Argument Category in the previous example can have the value (atom) sys_config (white on blue), sys_state (black on yellow), or error (white on red).

You can order Common Test to repeat the tests you specify. You can choose to repeat tests a number of times, repeat tests for a specific period of time, or repeat tests until a particular stop time is reached. If repetition is controlled by time, an action for Common Test to take upon time-out can be specified. Either Common Test performs all tests in the current run before stopping, or it stops when the current test job is finished. Repetition can be activated by ct_run start flags, or tuples in the ct:run:test/1 option list argument. The flags (options in parentheses) are the following:

When time-out occurs, Common Test never aborts the ongoing test case, as this can leave the SUT in an undefined, and possibly bad, state. Instead Common Test, by default, finishes the current test run before stopping. If flag force_stop is specified, Common Test stops when the current test job is finished. If flag force_stop is specified with skip_rest, Common Test only completes the current test case and skips the remaining tests in the test job.

Log files from every repeated test run is saved in normal Common Test fashion (described earlier).

Common Test might later support an optional feature to only store the last (and possibly the first) set of logs of repeated test runs, but for now the user must be careful not to run out of disk space if tests are repeated during long periods of time.

For each test run that is part of a repeated session, information about the particular test run is printed in the Common Test Framework Log. The information includes the repetition number, remaining time, and so on.

Example 1:

 $ ct_run -dir $TEST_ROOT/to1 $TEST_ROOT/to2 -duration 001000 -force_stop

Here, the suites in test directory to1, followed by the suites in to2, are executed in one test run. A time-out event occurs after 10 minutes. As long as there is time left, Common Test repeats the test run (that is, starting over with test to1). After time-out, Common Test stops when the current job is finished (because of flag force_stop). As a result, the specified test run can be aborted after test to1 and before test to2.

Example 2:

 $ ct_run -dir $TEST_ROOT/to1 $TEST_ROOT/to2 -duration 001000 -forces_stop skip_rest

Here, the same tests as in Example 1 are run, but with flag force_stop set to skip_rest. If time-out occurs while executing tests in directory to1, the remaining test cases in to1 are skipped and the test is aborted without running the tests in to2 another time. If time-out occurs while executing tests in directory to2, the remaining test cases in to2 are skipped and the test is aborted.

Example 3:

 $ date
 Fri Sep 28 15:00:00 MEST 2007

 $ ct_run -dir $TEST_ROOT/to1 $TEST_ROOT/to2 -until 160000

Here, the same test run as in the previous examples are executed (and possibly repeated). However, when the time-out occurs, after 1 hour, Common Test finishes the entire test run before stopping (that is, both to1 and to2 are always executed in the same test run).

Example 4:

 $ ct_run -dir $TEST_ROOT/to1 $TEST_ROOT/to2 -repeat 5

Here, the test run, including both the to1 and the to2 test, is repeated five times.

The protocol handling processes in Common Test, implemented by ct_telnet, ct_ssh, ct_ftp, and so on, do verbose printing to the test case logs. This can be switched off with flag -silent_connections:

 ct_run -silent_connections [conn_types]

Here, conn_types specifies SSH, Telnet, FTP, RPC, and/or SNMP.

Example 1:

 ct_run ... -silent_connections ssh telnet

This switches off logging for SSH and Telnet connections.

Example 2:

 ct_run ... -silent_connections

This switches off logging for all connection types.

Fatal communication error and reconnection attempts are always printed, even if logging has been suppressed for the connection type in question. However, operations such as sending and receiving data are performed silently.

silent_connections can also be specified in a test suite. This is accomplished by returning a tuple, {silent_connections,ConnTypes}, in the suite/0 or test case information list. If ConnTypes is a list of atoms (SSH, Telnet, FTP, RPC and/or SNMP), output for any corresponding connections are suppressed. Full logging is by default enabled for any connection of type not specified in ConnTypes. Hence, if ConnTypes is the empty list, logging is enabled for all connections.

Example 3:

 -module(my_SUITE).

 suite() -> [..., {silent_connections,[telnet,ssh]}, ...].

 ...

 my_testcase1() ->
     [{silent_connections,[ssh]}].

 my_testcase1(_) ->
     ...

 my_testcase2(_) ->
     ...

In this example, suite/0 tells Common Test to suppress printouts from Telnet and SSH connections. This is valid for all test cases. However, my_testcase1/0 specifies that for this test case, only SSH is to be silent. The result is that my_testcase1 gets Telnet information (if any) printed in the log, but not SSH information. my_testcase2 gets no information from either connection printed.

silent_connections can also be specified with a term in a test specification (see section Test Specifications in section Running Tests and Analyzing Results). Connections provided with start flag/option silent_connections are merged with any connections listed in the test specification.

Start flag/option silent_connections and the test specification term override any settings made by the information functions inside the test suite.