path: root/lib/common_test/doc/src/run_test_chapter.xml

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<!DOCTYPE chapter SYSTEM "chapter.dtd">

<chapter>
  <header>
    <copyright>
      <year>2003</year><year>2012</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      The contents of this file are subject to the Erlang Public License,
      Version 1.1, (the "License"); you may not use this file except in
      compliance with the License. You should have received a copy of the
      Erlang Public License along with this software. If not, it can be
      retrieved online at http://www.erlang.org/.

      Software distributed under the License is distributed on an "AS IS"
      basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
      the License for the specific language governing rights and limitations
      under the License.

    </legalnotice>

    <title>Running Tests</title>
    <prepared>Peter Andersson, Kenneth Lundin</prepared>
    <docno></docno>
    <date></date>
    <rev></rev>
    <file>run_test_chapter.xml</file>
  </header>

  <section>
    <title>Using the Common Test Framework</title>

    <p>The Common Test Framework provides a high level
    operator interface for testing. It adds the following features to
    the Erlang/OTP Test Server:</p>

    <list>
	<item>Automatic compilation of test suites (and help modules).</item>
	<item>Creation of additional HTML pages for better overview.</item>
	<item>Single command interface for running all available tests.</item>
	<item>Handling of configuration files specifying data related to
	  the System Under Test (and any other variable data).</item>
	<item>Mode for running multiple independent test sessions in parallel with
	  central control and configuration.</item>	
      </list>
  </section>

  <section>
    <title>Automatic compilation of test suites and help modules</title>
    <p>When Common Test starts, it will automatically attempt to compile any
      suites included in the specified tests. If particular
      suites have been specified, only those suites will be compiled. If a
      particular test object directory has been specified (meaning all suites
      in this directory should be part of the test), Common Test runs
      make:all/1 in the directory to compile the suites.</p>

    <p>If compilation should fail for one or more suites, the compilation errors
      are printed to tty and the operator is asked if the test run should proceed
      without the missing suites, or be aborted. If the operator chooses to proceed, 
      it is noted in the HTML log which tests have missing suites.</p>

    <p>Any help module (i.e. 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, will also be automatically compiled. A help
      module will not be mistaken for a test suite (unless it has a "_SUITE"
      name of course). 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.</p>

    <p>If test suites or help modules include header files stored in other
      locations than the test directory, you may specify these include directories
      by means of the <c><![CDATA[-include]]></c> flag with <c><![CDATA[ct_run]]></c>, 
      or the <c><![CDATA[include]]></c> option with <c><![CDATA[ct:run_test/1]]></c>.
      In addition to this, an include path may be specified with an OS
      environment variable; <c><![CDATA[CT_INCLUDE_PATH]]></c>. Example (bash):</p>

    <p><c>$ export CT_INCLUDE_PATH=~testuser/common_suite_files/include:~testuser/common_lib_files/include</c></p>

    <p>Common Test will pass all include directories (specified either with the
      <c><![CDATA[include]]></c> flag/option, or the <c><![CDATA[CT_INCLUDE_PATH]]></c>
      variable, or both) to the compiler.</p>

    <p>It is also possible to specify include directories in test specifications 
      (see below).</p>

    <p>If the user wants to run all test suites for a test object (or OTP application)
      by specifying only the top directory (e.g. with the <c>dir</c> start flag/option),
      Common Test will primarily look for test suite modules in a subdirectory named 
      <c>test</c>. If this subdirectory doesn't exist, the specified top directory
      is assumed to be the actual test directory, and test suites will be read from
      there instead.</p>

    <p>It is possible to disable the automatic compilation feature by using the
      <c><![CDATA[-no_auto_compile]]></c> flag with <c><![CDATA[ct_run]]></c>, or
      the <c><![CDATA[{auto_compile,false}]]></c> option with 
      <c><![CDATA[ct:run_test/1]]></c>. 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 can not be loaded
      from the local file system during startup of Common Test, the user needs to
      pre-load the modules before starting the test. Common Test will only verify
      that the specified test suites exist (i.e. that they are, or can be, loaded).
      This is useful e.g. if the test suites are transferred and loaded as binaries via
      RPC from a remote node.</p>
  </section>

  <marker id="ct_run"></marker>
  <section>
    <title>Running tests from the OS command line</title>
    
    <p>The <c>ct_run</c> program can be used for running tests from
      the OS command line, e.g.
    </p>
    <list>
      <item><c><![CDATA[ct_run -config <configfilenames> -dir <dirs>]]></c></item>
      <item><c><![CDATA[ct_run -config <configfilenames> -suite <suiteswithfullpath>]]></c>
      </item>
      <item><c><![CDATA[ct_run -userconfig <callbackmodulename> <configfilenames> -suite <suiteswithfullpath>]]></c>
      </item>
      <item><c><![CDATA[ct_run -config <configfilenames> -suite <suitewithfullpath>
	      -group <groupnames> -case <casenames>]]></c></item>
    </list>
    <p>Examples:</p>
    <p><c>$ ct_run -config $CFGS/sys1.cfg $CFGS/sys2.cfg -dir $SYS1_TEST $SYS2_TEST</c></p>
    <p><c>$ ct_run -userconfig ct_config_xml $CFGS/sys1.xml $CFGS/sys2.xml -dir $SYS1_TEST $SYS2_TEST</c></p>
    <p><c>$ ct_run -suite $SYS1_TEST/setup_SUITE $SYS2_TEST/config_SUITE</c></p>
    <p><c>$ ct_run -suite $SYS1_TEST/setup_SUITE -case start stop</c></p>
    <p><c>$ ct_run -suite $SYS1_TEST/setup_SUITE -group installation -case start stop</c></p>
    
    <p>It is also possible to combine the <c>dir</c>, <c>suite</c> and <c>group/case</c> flags. E.g, to run
    <c>x_SUITE</c> and <c>y_SUITE</c> in directory <c>testdir</c>:</p>

    <p><c>$ ct_run -dir ./testdir -suite x_SUITE y_SUITE</c></p>

    <p>This has the same effect as calling:</p>

    <p><c>$ ct_run -suite ./testdir/x_SUITE ./testdir/y_SUITE</c></p>

    <p>Other flags that may be used with <c>ct_run</c>:</p>
    <list>
      <item><c><![CDATA[-logdir <dir>]]></c>, specifies where the HTML log files are to be written.</item>
      <item><c><![CDATA[-label <name_of_test_run>]]></c>, associates the test run with a name that gets printed
	in the overview HTML log files.</item>
      <item><c>-refresh_logs</c>, refreshes the top level HTML index files.</item>
      <item><c>-vts</c>, start web based GUI (see below).</item>
      <item><c>-shell</c>, start interactive shell mode (see below).</item>
      <item><c>-step [step_opts]</c>, step through test cases using the Erlang Debugger (see below).</item>
      <item><c><![CDATA[-spec <testspecs>]]></c>, use test specification as input (see below).</item>
      <item><c>-allow_user_terms</c>, allows user specific terms in a test specification (see below).</item>
      <item><c>-silent_connections [conn_types]</c>, tells Common Test to suppress printouts for
        specified connections (see below).</item>
      <item><c><![CDATA[-stylesheet <css_file>]]></c>, points out a user HTML style sheet (see below).</item>
      <item><c><![CDATA[-cover <cover_cfg_file>]]></c>, to perform code coverage test (see 
	<seealso marker="cover_chapter#cover">Code Coverage Analysis</seealso>).</item>
      <item><c><![CDATA[-event_handler <event_handlers>]]></c>, to install 
        <seealso marker="event_handler_chapter#event_handling">event handlers</seealso>.</item>
      <item><c><![CDATA[-event_handler_init <event_handlers>]]></c>, to install
        <seealso marker="event_handler_chapter#event_handling">event handlers</seealso> including start arguments.</item>
      <item><c><![CDATA[-ct_hooks <ct_hooks>]]></c>, to install
        <seealso marker="ct_hooks_chapter#installing">Common Test Hooks</seealso> including start arguments.</item>
      <item><c><![CDATA[-enable_builtin_hooks <bool>]]></c>, to enable/disable
        <seealso marker="ct_hooks_chapter#builtin_cths">Built-in Common Test Hooks</seealso>. Default is <c>true</c>.</item>
      <item><c><![CDATA[-include]]></c>, specifies include directories (see above).</item>
      <item><c><![CDATA[-no_auto_compile]]></c>, disables the automatic test suite compilation feature (see above).</item>
      <item><c><![CDATA[-multiply_timetraps <n>]]></c>, extends <seealso marker="write_test_chapter#timetraps">timetrap
	  timeout</seealso> values.</item>
      <item><c><![CDATA[-scale_timetraps <bool>]]></c>, enables automatic <seealso marker="write_test_chapter#timetraps">timetrap
	  timeout</seealso> scaling.</item>
      <item><c><![CDATA[-repeat <n>]]></c>, tells Common Test to repeat the tests n times (see below).</item> 
      <item><c><![CDATA[-duration <time>]]></c>, tells Common Test to repeat the tests for duration of time (see below).</item> 
      <item><c><![CDATA[-until <stop_time>]]></c>, tells Common Test to repeat the tests until stop_time (see below).</item> 
      <item><c>-force_stop</c>, on timeout, the test run will be aborted when current test job is finished (see below).</item>
      <item><c><![CDATA[-decrypt_key <key>]]></c>, provides a decryption key for 
        <seealso marker="config_file_chapter#encrypted_config_files">encrypted configuration files</seealso>.</item>
      <item><c><![CDATA[-decrypt_file <key_file>]]></c>, points out a file containing a decryption key for 
        <seealso marker="config_file_chapter#encrypted_config_files">encrypted configuration files</seealso>.</item>
      <item><c><![CDATA[-basic_html]]></c>, switches off html enhancements that might not be compatible with older browsers.</item>
      <item><c><![CDATA[-logopts <opts>]]></c>, makes it possible to modify aspects of the logging behaviour, see
        <seealso marker="run_test_chapter#logopts">Log options</seealso> below.</item>
      <item><c><![CDATA[-verbosity <levels>]]></c>, sets <seealso marker="write_test_chapter#logging">verbosity levels
      for printouts</seealso>.</item>
    </list>

    <note><p>Directories passed to Common Test may have either relative or absolute paths.</p></note>

    <note><p>Arbitrary start flags to the Erlang Runtime System may also be passed as
             parameters to <c>ct_run</c>. It is, for example, useful to be able to
	     pass directories that should be added to the Erlang code server search path
	     with the <c>-pa</c> or <c>-pz</c> flag. If you have common help- or library 
	     modules for test suites (separately compiled), stored in other directories 
	     than the test suite directories, these help/lib directories are preferrably
	     added to the code path this way. Example:</p>
	  <p><c>$ ct_run -dir ./chat_server -logdir ./chat_server/testlogs -pa $PWD/chat_server/ebin</c></p>
	  <p>Note how in this example, the absolute path of the <c>chat_server/ebin</c>
	     directory is passed to the code server. This is essential since relative
	     paths are stored by the code server as relative, and Common Test changes 
	     the current working directory of the Erlang Runtime System during the test run!</p>
    </note>
    
    <p>The <c>ct_run</c> program sets the exit status before shutting down. The following values
      are defined:</p>
    <list>
      <item><c>0</c> indicates a successful testrun, i.e. one without failed or auto-skipped test cases.</item>
      <item><c>1</c> indicates that one or more test cases have failed, or have been auto-skipped.</item>
      <item><c>2</c> indicates that the test execution has failed because of e.g. compilation errors, an
	illegal return value from an info function, etc.</item>
    </list>
    <p>If auto-skipped test cases should not affect the exit status, you may change the default
      behaviour using start flag:</p>
    <pre>-exit_status ignore_config</pre>
    
    <p>For more information about the <c>ct_run</c> program, see the
      <seealso marker="ct_run#top">Reference Manual</seealso> and the
      <seealso marker="install_chapter#general">Installation</seealso> chapter.
    </p>
  </section>
    
  <section>
    <title>Running tests from the Erlang shell or from an Erlang program</title>
    
    <p>Common Test provides an Erlang API for running tests. The main (and most
      flexible) function for specifying and executing tests is called
      <c><seealso marker="ct#run_test-1">ct:run_test/1</seealso></c>.
      This function takes the same start parameters as
      the <c><seealso marker="run_test_chapter#ct_run">ct_run</seealso></c>
      program described above, only the flags are instead
      given as options in a list of key-value tuples. E.g. a test specified 
      with <c>ct_run</c> like:</p>

      <p><c>$ ct_run -suite ./my_SUITE -logdir ./results</c></p> 
      <p>is with <c><seealso marker="ct#run_test-1">ct:run_test/1</seealso></c> specified as:</p>
      <p><c>1> ct:run_test([{suite,"./my_SUITE"},{logdir,"./results"}]).</c></p>

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

	<section>
	  <title>Releasing the Erlang shell</title>
	  <p>During execution of tests, started with
	  <c><seealso marker="ct#run_test-1">ct:run_test/1</seealso></c>,
	  the Erlang shell process, controlling stdin, will remain the top
	  level process of the Common Test system of processes. The result
	  is that the Erlang shell is not available for interaction during
	  the test run. If this is not desirable, maybe because the shell is needed
	  for debugging purposes or for interaction with the SUT during test
	  execution, you may set the <c>release_shell</c> start option to
	  <c>true</c> (in the call to <c>ct:run_test/1</c> or by
	  using the corresponding test specification term, see below). This will
	  make Common Test release the shell immediately after the test suite
	  compilation stage. To accomplish this, a test runner process
	  is spawned to take control of the test execution, and the effect is that
	  <c>ct:run_test/1</c> returns the pid of this process rather than the
	  test result - which instead is printed to tty at the end of the test run.</p>
	  <note><p>Note that in order to use the
	  <c><seealso marker="ct#break-1">ct:break/1/2</seealso></c> and
	  <c><seealso marker="ct#continue-0">ct:continue/0/1</seealso></c> functions,
	  <c>release_shell</c> <em>must</em> be set to <c>true</c>.</p></note>
	</section>
        
      <p>For detailed documentation about
        <c><seealso marker="ct#run_test-1">ct:run_test/1</seealso></c>,
        please see the
        <c><seealso marker="ct#run_test-1">ct</seealso></c> manual page.</p>    
  </section>
  
  <section>
    <title>Running the interactive shell mode</title>
    
    <p>You can start Common Test in an interactive shell mode where no
      automatic testing is performed. Instead, in this mode, 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.</p>

    <p>The shell mode is useful e.g. for debugging test suites, for analysing
      and debugging the SUT during "simulated" test case execution, and 
      for trying out various operations during test suite development.</p>

    <p>To invoke the interactive shell mode, you can start an Erlang shell 
      manually and call <c><seealso marker="ct#install-1">ct:install/1</seealso></c> to install any configuration
      data you might need (use <c>[]</c> as argument otherwise), then
      call <c><seealso marker="ct#start_interactive-0">ct:start_interactive/0</seealso></c> to start Common Test. If you use
      the <c>ct_run</c> program, you may start the Erlang shell and Common Test
      in the same go by using the <c>-shell</c> and, optionally, the <c>-config</c>
      and/or <c>-userconfig</c> flag. Examples:
    </p>
    <list>
      <item><c>ct_run -shell</c></item>
      <item><c><![CDATA[ct_run -shell -config cfg/db.cfg]]></c></item>
      <item><c><![CDATA[ct_run -shell -userconfig db_login testuser x523qZ]]></c></item>
    </list>
    
    <p>If no config file is given with the <c>ct_run</c> command,
      a warning will be displayed. If Common Test has been run from the same
      directory earlier, the same config file(s) will be used
      again. If Common Test has not been run from this directory before, no
      config files will be available.</p>
    
    <p>If any functions using "required config data" (e.g. ct_telnet or
      ct_ftp functions) are to be called from the erlang shell, config
      data must first be required with <c><seealso marker="ct#require-1">
      ct:require/1/2</seealso></c>. This is
      equivalent to a <c>require</c> statement in the <seealso
	marker="write_test_chapter#suite">Test Suite Info 
	Function</seealso> or in the <seealso
	marker="write_test_chapter#info_function">Test Case Info
	Function</seealso>.</p>
    
    <p>Example:</p>
    <pre> 
       1> ct:require(unix_telnet, unix).
       ok
       2> ct_telnet:open(unix_telnet).
       {ok,&lt;0.105.0&gt;}
       4> ct_telnet:cmd(unix_telnet, "ls .").
       {ok,["ls .","file1  ...",...]}
    </pre>
    
    <p>Everything that Common Test normally prints in the test case logs,
      will in the interactive mode be written to a log named
      <c>ctlog.html</c> in the <c><![CDATA[ct_run.<timestamp>]]></c>
      directory. A link to this file will be available in the file
      named <c>last_interactive.html</c> in the directory from which
      you executed <c>ct_run</c>. Currently, specifying a different
      root directory for the logs than the current working directory,
      is not supported.</p>
    
    <p>If you wish to exit the interactive mode (e.g. to start an
      automated test run with <c><seealso marker="ct#run_test-1">ct:run_test/1</seealso></c>), call the function
      <c><seealso marker="ct#stop_interactive-0">ct:stop_interactive/0</seealso></c>. This shuts down the
      running <c>ct</c> application. Associations between
      configuration names and data created with <c>require</c> are 
      consequently deleted. <c><seealso marker="ct#start_interactive-0">ct:start_interactive/0</seealso></c> will get you
      back into interactive mode, but the previous state is not restored.</p>
  </section>

  <section>
    <title>Step by step execution of test cases with the Erlang Debugger</title>
   
    <p>By means of <c>ct_run -step [opts]</c>, or by passing the 
       <c>{step,Opts}</c> option to <c><seealso marker="ct#run_test-1">ct:run_test/1</seealso></c>, it is possible
       to get the Erlang Debugger started automatically and use its
       graphical interface to investigate the state of the current test 
       case and to execute it step by step and/or set execution breakpoints.</p>
    <p>If no extra options are given with the <c>step</c> flag/option,
       breakpoints will be set automatically on the test cases that
       are to be executed by Common Test, and those functions only. If
       the step option <c>config</c> is specified, breakpoints will 
       also be initially set on the configuration functions in the suite, i.e.
       <c>init_per_suite/1</c>, <c>end_per_suite/1</c>,
       <c>init_per_group/2</c>, <c>end_per_group/2</c>,
       <c>init_per_testcase/2</c> and <c>end_per_testcase/2</c>.</p>
    <p>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 will automatically pop up. (This is because each test 
       case executes on a dedicated Erlang process). Whenever a new test case starts,
       Common Test will attempt to close the inactive trace window of the previous 
       test case. However, if you prefer that Common Test leaves inactive trace 
       windows, use the <c>keep_inactive</c> option.</p>
    <p>The step functionality can be used together with the <c>suite</c> and 
       the <c>suite</c> + <c>case/testcase</c> flag/option, but not together 
       with <c>dir</c>.</p>       
  </section>

  <marker id="test_specifications"></marker>
  <section>
    <title>Test Specifications</title>
    
    <p>The most flexible way to specify what to test, is to use a so
      called test specification. A test specification is a sequence of
      Erlang terms. The terms are normally declared in a text file (see
      <c><seealso marker="ct#run_test-1">ct:run_test/1</seealso></c>), but
      may also be passed to Common Test on the form of a list (see
      <c><seealso marker="ct#run_testspec-1">ct:run_testspec/1</seealso></c>).
      There are two general types of terms: configuration terms and test
      specification terms.</p>
    <p>With configuration terms it is possible to e.g. label the test
      run (similar to <c>ct_run -label</c>), evaluate arbitrary expressions
      before starting the test, import configuration data (similar to
      <c>ct_run -config/-userconfig</c>), specify the top level HTML log
      directory (similar to <c>ct_run -logdir</c>), enable code coverage
      analysis (similar to <c>ct_run -cover</c>), install Common Test Hooks
      (similar to <c>ct_run -ch_hooks</c>), install event_handler plugins
      (similar to <c>ct_run -event_handler</c>), specify include directories
      that should be passed to the compiler for automatic compilation
      (similar to <c>ct_run -include</c>), disable the auto compilation
      feature (similar to <c>ct_run -no_auto_compile</c>), set verbosity
      levels (similar to <c>ct_run -verbosity</c>), and more.</p>
    <p>Configuration terms can be combined with <c>ct_run</c> start flags,
      or <c>ct:run_test/1</c> options. The result will for some flags/options
      and terms be that the values are merged (e.g. configuration files,
      include directories, verbosity levels, silent connections), and for
      others that the start flags/options override the test specification
      terms (e.g. log directory, label, style sheet, auto compilation).</p>
    <p>With test specification terms it is possible to state exactly
      which tests should run and in which order. A test term specifies
      either one or more suites, one or more test case groups, or one
      or more test cases in a group or suite.</p>
    <p>An arbitrary number of test terms may be declared in sequence.
      Common Test will by default compile the terms into one or more tests 
      to be performed in one resulting test run. Note that a term that
      specifies a set of test cases will "swallow" one that only
      specifies a subset of these cases. E.g. the result of merging
      one term that specifies that all cases in suite S should be
      executed, with another term specifying only test case X and Y in
      S, is a test of all cases in S. However, if a term specifying
      test case X and Y in S is merged with a term specifying case Z
      in S, the result is a test of X, Y and Z in S. To disable this
      behaviour, i.e. to instead perform each test sequentially in a "script-like"
      manner, the term <c>merge_tests</c> can be set to <c>false</c> in
      the test specification.</p>
    <p>A test term can also specify one or more test suites, groups,
      or test cases to be skipped. Skipped suites, groups and cases
      are not executed and show up in the HTML log files as
      SKIPPED.</p>
    <p>When a test case group is specified, the resulting test
      executes the
      <c>init_per_group</c> function, followed by all test cases and
      sub groups (including their configuration functions), and
      finally the <c>end_per_group</c> function. Also if particular
      test cases in a group are specified, <c>init_per_group</c>
      and <c>end_per_group</c> for the group in question are
      called. If a group which is defined (in <c>Suite:group/0</c>) to
      be a sub group of another group, is specified (or particular test
      cases of a sub group are), Common Test will call the configuration
      functions for the top level groups as well as for the sub group
      in question (making it possible to pass configuration data all
      the way from <c>init_per_suite</c> down to the test cases in the
      sub group).</p>

    <p>With the <c>GroupSpec</c> element (below) it's possible to specify
      group execution properties that will override those specified in the
      group definition (i.e. in <c>groups/0</c>). Execution properties for
      sub-groups may be overridden as well. This feature makes it possible to
      change properties of groups at the time of execution,
      without even having to edit the test suite. More detailed documentation,
      and examples, can be found in the
      <seealso marker="write_test_chapter#test_case_groups">
      Test case groups</seealso> chapter.</p>

    <p>Below is the test specification syntax. Test specifications can
      be used to run tests both in a single test host environment and
      in a distributed Common Test environment (Large Scale
      Testing). The node parameters in the <c>init</c> term are only
      relevant in the latter (see the
      <seealso marker="ct_master_chapter#test_specifications">Large
      Scale Testing</seealso> chapter for information). For more information
      about the various terms, please see the corresponding sections in the
      User's Guide, such as e.g. the
      <seealso marker="run_test_chapter#ct_run"><c>ct_run</c>
      program</seealso> for an overview of available start flags
      (since most flags have a corresponding configuration term), and
      more detailed explanation of e.g.
      <seealso marker="write_test_chapter#logging">Logging</seealso>
      (for the <c>verbosity</c>, <c>stylesheet</c> and <c>basic_html</c> terms),
      <seealso marker="config_file_chapter#top">External Configuration Data</seealso>
      (for the <c>config</c> and <c>userconfig</c> terms),      
      <seealso marker="event_handler_chapter#event_handling">Event
      Handling</seealso> (for the <c>event_handler</c> term),
      <seealso marker="ct_hooks_chapter#installing">Common Test Hooks</seealso>
      (for the <c>ct_hooks</c> term), etc.</p>
      <p>Config terms:</p>
    <pre>
      {merge_tests, Bool}.

      {define, Constant, Value}.

      {node, NodeAlias, Node}.

      {init, InitOptions}.
      {init, [NodeAlias], InitOptions}.

      {label, Label}.
      {label, NodeRefs, Label}.

      {verbosity, VerbosityLevels}.
      {verbosity, NodeRefs, VerbosityLevels}.

      {stylesheet, CSSFile}.
      {stylesheet, NodeRefs, CSSFile}.

      {silent_connections, ConnTypes}.
      {silent_connections, NodeRefs, ConnTypes}.

      {multiply_timetraps, N}.
      {multiply_timetraps, NodeRefs, N}.

      {scale_timetraps, Bool}.
      {scale_timetraps, NodeRefs, Bool}.
 
      {cover, CoverSpecFile}.
      {cover, NodeRefs, CoverSpecFile}.
      
      {include, IncludeDirs}.
      {include, NodeRefs, IncludeDirs}.

      {auto_compile, Bool},
      {auto_compile, NodeRefs, Bool},

      {config, ConfigFiles}.
      {config, ConfigDir, ConfigBaseNames}.
      {config, NodeRefs, ConfigFiles}.
      {config, NodeRefs, ConfigDir, ConfigBaseNames}.

      {userconfig, {CallbackModule, ConfigStrings}}.
      {userconfig, NodeRefs, {CallbackModule, ConfigStrings}}.
      
      {logdir, LogDir}.                                        
      {logdir, NodeRefs, LogDir}.

      {logopts, LogOpts}.
      {logopts, NodeRefs, LogOpts}.

      {create_priv_dir, PrivDirOption}.
      {create_priv_dir, NodeRefs, PrivDirOption}.
      
      {event_handler, EventHandlers}.
      {event_handler, NodeRefs, EventHandlers}.
      {event_handler, EventHandlers, InitArgs}.
      {event_handler, NodeRefs, EventHandlers, InitArgs}.

      {ct_hooks, CTHModules}.
      {ct_hooks, NodeRefs, CTHModules}.

      {enable_builtin_hooks, Bool}.
      
      {basic_html, Bool}.
      {basic_html, NodeRefs, Bool}.

      {release_shell, Bool}.</pre>

      <p>Test terms:</p>
    <pre>
      {suites, Dir, Suites}.                                
      {suites, NodeRefs, Dir, Suites}.
      
      {groups, Dir, Suite, Groups}.
      {groups, NodeRefs, Dir, Suite, Groups}.

      {groups, Dir, Suite, GroupSpec, {cases,Cases}}.
      {groups, NodeRefs, Dir, Suite, GroupSpec, {cases,Cases}}.

      {cases, Dir, Suite, Cases}.                           
      {cases, NodeRefs, Dir, Suite, Cases}.

      {skip_suites, Dir, Suites, Comment}.
      {skip_suites, NodeRefs, Dir, Suites, Comment}.

      {skip_groups, Dir, Suite, GroupNames, Comment}.
      {skip_groups, NodeRefs, Dir, Suite, GroupNames, Comment}.
      
      {skip_cases, Dir, Suite, Cases, Comment}.
      {skip_cases, NodeRefs, Dir, Suite, Cases, Comment}.</pre>

      <p>Types:</p>
    <pre>
      Bool            = true | false
      Constant        = atom()
      Value           = term()
      NodeAlias       = atom()
      Node            = node()
      NodeRef         = NodeAlias | Node | master
      NodeRefs        = all_nodes | [NodeRef] | NodeRef
      InitOptions     = term()
      Label           = atom() | string()
      VerbosityLevels = integer() | [{Category,integer()}]
      Category        = atom()
      CSSFile         = string()
      ConnTypes       = all | [atom()]
      N               = integer()
      CoverSpecFile   = string()
      IncludeDirs     = string() | [string()]
      ConfigFiles     = string() | [string()]
      ConfigDir       = string()
      ConfigBaseNames = string() | [string()]
      CallbackModule  = atom()
      ConfigStrings   = string() | [string()]
      LogDir          = string()
      LogOpts         = [term()]
      PrivDirOption   = auto_per_run | auto_per_tc | manual_per_tc
      EventHandlers   = atom() | [atom()]
      InitArgs        = [term()]
      CTHModules      = [CTHModule | {CTHModule, CTHInitArgs} | {CTHModule, CTHInitArgs, CTHPriority}]
      CTHModule       = atom()
      CTHInitArgs     = term()
      Dir             = string()
      Suites          = atom() | [atom()] | all
      Suite           = atom()
      Groups          = GroupSpec | [GroupSpec] | all
      GroupSpec       = GroupName | {GroupName,Properties} | {GroupName,Properties,GroupSpec}
      GroupName       = atom()
      GroupNames      = GroupName | [GroupName]
      Cases           = atom() | [atom()] | all
      Comment         = string() | ""</pre>

    <p>The difference between the <c>config</c> terms above, is that with
      <c>ConfigDir</c>, <c>ConfigBaseNames</c> is a list of base names,
      i.e. without directory paths. <c>ConfigFiles</c> must be full names,
      including paths. E.g, these two terms have the same meaning:</p>
    <pre>
      {config, ["/home/testuser/tests/config/nodeA.cfg",
                "/home/testuser/tests/config/nodeB.cfg"]}.

      {config, "/home/testuser/tests/config", ["nodeA.cfg","nodeB.cfg"]}.</pre>

    <note><p>Any relative paths specified in the test specification, will be
	relative to the directory which contains the test specification file, if
	<c>ct_run -spec TestSpecFile ...</c> or
	<c>ct:run:test([{spec,TestSpecFile},...])</c>
	executes the test. The path will be relative to the top level log directory, if
	<c>ct:run:testspec(TestSpec)</c> executes the test.</p></note>
      
    <p>The <c>define</c> term introduces a constant, which is used to
      replace the name <c>Constant</c> with <c>Value</c>, wherever it's found in
      the test specification. This replacement happens during an initial iteration
      through the test specification. Constants may be used anywhere in the test
      specification, e.g. in arbitrary lists and tuples, and even in strings
      and inside the value part of other constant definitions! A constant can
      also be part of a node name, but that is the only place where a constant
      can be part of an atom.</p>
    
    <note><p>For the sake of readability, the name of the constant must always
	begin with an upper case letter, or a <c>$</c>, <c>?</c>, or <c>_</c>.
	This also means that it must always be single quoted (obviously, since
	the constant name is actually an atom, not text).</p></note>

    <p>The main benefit of constants is that they can be used to reduce the size
      (and avoid repetition) of long strings, such as file paths. Compare these
      terms:</p>

    <pre>
      %% 1a. no constant
      {config, "/home/testuser/tests/config", ["nodeA.cfg","nodeB.cfg"]}.
      {suites, "/home/testuser/tests/suites", all}.
      
      %% 1b. with constant
      {define, 'TESTDIR', "/home/testuser/tests"}.
      {config, "'TESTDIR'/config", ["nodeA.cfg","nodeB.cfg"]}.
      {suites, "'TESTDIR'/suites", all}.

      %% 2a. no constants
      {config, [testnode@host1, testnode@host2], "../config", ["nodeA.cfg","nodeB.cfg"]}.
      {suites, [testnode@host1, testnode@host2], "../suites", [x_SUITE, y_SUITE]}.

      %% 2b. with constants
      {define, 'NODE', testnode}.
      {define, 'NODES', ['NODE'@host1, 'NODE'@host2]}.
      {config, 'NODES', "../config", ["nodeA.cfg","nodeB.cfg"]}.
      {suites, 'NODES', "../suites", [x_SUITE, y_SUITE]}.</pre>

    <p>Constants make the test specification term <c>alias</c>, in previous
      versions of Common Test, redundant. This term has been deprecated but will
      remain supported in upcoming Common Test releases. Replacing <c>alias</c>
      terms with <c>define</c> is strongly recommended though! Here's an example
      of such a replacement:</p>

    <pre>
      %% using the old alias term
      {config, "/home/testuser/tests/config/nodeA.cfg"}.
      {alias, suite_dir, "/home/testuser/tests/suites"}.
      {groups, suite_dir, x_SUITE, group1}.

      %% replacing with constants
      {define, 'TestDir', "/home/testuser/tests"}.
      {define, 'CfgDir', "'TestDir'/config"}.
      {define, 'SuiteDir', "'TestDir'/suites"}.
      {config, 'CfgDir', "nodeA.cfg"}.
      {groups, 'SuiteDir', x_SUITE, group1}.</pre>

    <p>Actually, constants could well replace the <c>node</c> term too, but
      this still has declarative value, mainly when used in combination
      with <c>NodeRefs == all_nodes</c> (see types above).</p>

    <p>Here follows a simple test specification example:</p>
    <pre>
      {define, 'Top', "/home/test"}.
      {define, 'T1', "'Top'/t1"}.
      {define, 'T2', "'Top'/t2"}.
      {define, 'T3', "'Top'/t3"}.
      {define, 'CfgFile', "config.cfg"}.

      {logdir, "'Top'/logs"}.
      
      {config, ["'T1'/'CfgFile'", "'T2'/'CfgFile'", "'T3'/'CfgFile'"]}.
      
      {suites, 'T1', all}.
      {skip_suites, 'T1', [t1B_SUITE,t1D_SUITE], "Not implemented"}.
      {skip_cases, 'T1', t1A_SUITE, [test3,test4], "Irrelevant"}.
      {skip_cases, 'T1', t1C_SUITE, [test1], "Ignore"}.
      
      {suites, 'T2', [t2B_SUITE,t2C_SUITE]}.
      {cases, 'T2', t2A_SUITE, [test4,test1,test7]}.
      
      {skip_suites, 'T3', all, "Not implemented"}.</pre>

    <p>The example specifies the following:</p>
    <list>
      <item>The specified logdir directory will be used for storing 
	the HTML log files (in subdirectories tagged with node name, 
	date and time).</item>
      <item>The variables in the specified test system config files will be 
	imported for the test.</item>
      <item>The first test to run includes all suites for system t1. Excluded from
	the test are however the t1B and t1D suites. Also test cases test3 and
	test4 in t1A as well as the test1 case in t1C are excluded from
	the test.</item>
      <item>Secondly, the test for system t2 should run. The included suites are
	t2B and t2C. Included are also test cases test4, test1 and test7 in suite
	t2A. Note that the test cases will be executed in the specified order.</item>
      <item>Lastly, all suites for systems t3 are to be completely skipped and this
	should be explicitly noted in the log files.</item>
    </list>
    <p>With the <c>init</c> term it's possible to specify initialization options
      for nodes defined in the test specification. Currently, there are options
      to start the node and/or to evaluate any function on the node.
      See the <seealso marker="ct_master_chapter#ct_slave">Automatic startup of
      the test target nodes</seealso> chapter for details.</p>
    <p>It is possible for the user to provide a test specification that
      includes (for Common Test) unrecognizable terms. If this is desired,
      the <c>-allow_user_terms</c> flag should be used when starting tests with
      <c>ct_run</c>. This forces Common Test to ignore unrecognizable terms.
      Note that in this mode, Common Test is not able to check the specification 
      for errors as efficiently as if the scanner runs in default mode. 
      If <c><seealso marker="ct#run_test-1">ct:run_test/1</seealso></c> is used for starting the tests, the relaxed scanner
      mode is enabled by means of the tuple: <c>{allow_user_terms,true}</c></p>
  </section>

  <section>
    <title>Running tests from the Web based GUI</title>
    
    <p>The web based GUI, VTS, is started with the
      <c><seealso marker="run_test_chapter#ct_run">ct_run</seealso></c>
      program. From the GUI you can load config files, and select
      directories, suites and cases to run. You can also state the
      config files, directories, suites and cases on the command line
      when starting the web based GUI.
    </p>
    
    <list>
      <item><c>ct_run -vts</c></item>
      <item><c><![CDATA[ct_run -vts -config <configfilename>]]></c></item>
      <item><c><![CDATA[ct_run -vts -config <configfilename> -suite <suitewithfullpath>
	      -case <casename>]]></c></item>
    </list>
    
    <p>From the GUI you can run tests and view the result and the logs.
    </p>
    
    <p>Note that <c>ct_run -vts</c> will try to open the Common Test start
      page in an existing web browser window or start the browser if it is
      not running. Which browser should be started may be specified with
      the browser start command option:</p>
      <p><c><![CDATA[ct_run -vts -browser <browser_start_cmd>]]></c></p>
      <p>Example:</p>
      <p><c><![CDATA[$ ct_run -vts -browser 'firefox&']]></c></p>
      <p>Note that the browser must run as a separate OS process or VTS will hang!</p>
      <p>If no specific browser start command is specified, Firefox will
        be the default browser on Unix platforms and Internet Explorer on Windows.
	If Common Test fails to start a browser automatically, or <c>'none'</c> is
	specified as the value for -browser (i.e. <c>-browser none</c>), start your
	favourite browser manually and type in the URL that Common Test
	displays in the shell.</p>    
  </section>
  
  <section>
    <marker id="log_files"></marker>
    <title>Log files</title>
    
    <p>As the execution of the test suites proceed, events are logged in
      four different ways:</p>
      
      <list>
	<item>Text to the operator's console.</item>
	<item>Suite related information is sent to the major log file.</item>
	<item>Case related information is sent to the minor log file.</item>
	<item>The HTML overview log file gets updated with test results.</item>
	<item>A link to all runs executed from a certain directory is written in
	  the log named "all_runs.html" and direct links to all tests (the
	  latest results) are written to the top level "index.html".</item>
      </list>
      
      <p>Typically the operator, who may run hundreds or thousands of
	test cases, doesn't want to fill the console with details
	about, or printouts from, the specific test cases. By default, the 
	operator will only see:</p>
      
      <list>
	<item>A confirmation that the test has started and information about how 
	  many test cases will be executed totally.</item>
	<item>A small note about each failed test case.</item>
	<item>A summary of all the run test cases.</item>
	<item>A confirmation that the test run is complete.</item>
	<item>Some special information like error reports and progress
	  reports, printouts written with erlang:display/1, or io:format/3
	  specifically addressed to a receiver other than <c>standard_io</c>
	  (e.g. the default group leader process 'user').</item>
      </list>

      <p>If/when the operator wants to dig deeper into the general results, or
        the result of a specific test case, he should do so by
	following the links in the HTML presentation and take a look in the
	major or minor log files. The "all_runs.html" page is a practical
	starting point usually. It's located in <c>logdir</c> and contains
	a link to each test run including a quick overview (date and time,
	node name, number of tests, test names and test result totals).</p>
	
      <p>An "index.html" page is written for each test run (i.e. stored in
	the "ct_run" directory tagged with node name, date and time). This
	file gives a short overview of all individual tests performed in the 
	same test run. The test names follow this convention:</p>
      <list>
	<item><em>TopLevelDir.TestDir</em> (all suites in TestDir executed)</item>
	<item><em>TopLevelDir.TestDir:suites</em> (specific suites were executed)</item>
	<item><em>TopLevelDir.TestDir.Suite</em> (all cases in Suite executed)</item>
	<item><em>TopLevelDir.TestDir.Suite:cases</em> (specific test cases were executed)</item>
	<item><em>TopLevelDir.TestDir.Suite.Case</em> (only Case was executed)</item>
      </list>
      
      <p>On the test run index page there is 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 very helpful when
	analyzing test results or debugging test suites.</p>

      <p>On the test run index page it is noted if a test has missing
        suites (i.e. suites that Common Test has failed to
        compile). Names of the missing suites can be found in the
        Common Test Framework log file.</p>

      <p>The major logfile shows a detailed report of the test run. It
        includes test suite and test case names, execution time, the 
	exact reason for failures etc. The information is available in both
	a file with textual and with HTML representation. The HTML file shows a 
	summary which 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.</p>
      
      <p>The minor log files contain full details of every single test
	case, each one in a separate file. This way, it should be
	straightforward	to compare the latest results to that of previous
	test runs, even if the set of test cases changes. If SASL is running,
	its logs will also be printed to the current minor log file by the
	<seealso marker="common_test:ct_hooks_chapter#builtin_cths">
	  cth_log_redirect built-in hook</seealso>.
      </p>

      <p>The full name of the minor log file (i.e. the name of the file
	including the absolute directory path) can be read during execution
	of the test case. It comes as value in the tuple
	<c>{tc_logfile,LogFileName}</c> in the <c>Config</c> 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.	Please see the
	<seealso marker="event_handler_chapter#event_handling">Event Handling</seealso>
	chapter for details.
      </p>
      
      <p>Which information goes where is user configurable via the
	test server controller. Three threshold values determine what
	comes out on screen, and in the major or minor log files. See
	the OTP Test Server manual for information. The	contents that 
	goes to the HTML log file is fixed however and cannot be altered.</p>

      <p>The log files are written continously during a test run and links are
	always created initially when a test starts. This makes it possible
	to follow test progress simply by refreshing pages in the HTML browser.
	Statistics totals are not presented until a test is complete however.</p>

	<section>
	  <marker id="logopts"></marker>
	  <title>Log options</title>
	  <p>With the <c>logopts</c> start flag, it's possible to specify
	  options that modify some aspects of the logging behaviour.
	  Currently, the following options are available:</p>
	  <list>
	    <item><c>no_src</c></item>
	    <item><c>no_nl</c></item>
	  </list>
	  <p>With <c>no_src</c>, the html version of the test suite source
	  code will not be generated during the test run (and consequently
	  not be available in the log file system).</p>
	  <p>With <c>no_nl</c>, Common Test will not add a newline character
	  (\n) to the end of an output string that it receives from a call to e.g.
	  <c>io:format/2</c>, and which it prints to the test case log.</p>
	  <p>For example, if a test is started with:</p>
	  <p><c>$ ct_run -suite my_SUITE -logopts no_src</c></p>
	  <p>then printouts during the test made by successive calls to <c>io:format("x")</c>,
	  will appear in the test case log as:</p>
	  <p><c>xxx</c></p>
	  <p>instead of each <c>x</c> printed on a new line, which is the default behaviour.</p>
	</section>

	<section>
	  <marker id="table_sorting"></marker>
	  <title>Sorting HTML table columns</title>
	  <p>By clicking the name in the column header of any table (e.g. "Ok", "Case", "Time", etc),
	    the table rows are sorted in whatever order makes sense for the type of value (e.g.
	    numerical for "Ok" or "Time", and alphabetical for "Case"). The sorting is performed
	    by means of JavaScript code, automatically inserted into the HTML log files. Common Test
	    uses the <url href="http://jquery.com">jQuery</url> library and the
	    <url href="http://tablesorter.com">tablesorter</url> plugin, with customized sorting
	    functions, for this implementation.</p>
	</section>
      </section>
  
      <section>
	<marker id="html_stylesheet"></marker>
	<title>HTML Style Sheets</title>
	<p>Common Test uses an HTML Style Sheet (CSS file) to control the look of
	  the HTML log files generated during test runs. If, for some reason, 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:</p>
	<pre>basic_html</pre>
	<p>This disables the use of Style Sheets, as well as JavaScripts (see
	  table sorting above).</p>
	  
	<p>Common Test includes an <em>optional</em> feature to allow
	  user HTML style sheets for customizing printouts. The
	  functions in <c>ct</c> that print to a test case HTML log
	  file (<c>log/3</c> and <c>pal/3</c>) accept <c>Category</c>
	  as first argument. With this argument it's possible to
	  specify a category 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 may
	  look like this:</p>

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

	<p>To install the CSS file (Common Test inlines the definition in the 
	  HTML code), the name may be provided when executing <c>ct_run</c>.
	  Example:</p>

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

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

	  <p>It is also possible to install style sheets on a per suite and
	  per test case basis. Example:</p>

	<pre>
	  -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).</pre>

	<p>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 can not be used by other suites. A suite private style sheet, 
	  if specified, will be used in favour of a global style sheet (one specified 
	  with the <c>-stylesheet</c> flag). A stylesheet tuple (as returned by <c>suite/0</c> 
	  above) can also be returned from a test case info 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 favour of a suite or 
	  global level style sheet.
	</p>

	<p>In a tuple <c>{stylesheet,CSSFile}</c>, if <c>CSSFile</c> is specified
	  with a path, e.g. <c>"$TEST/styles/categories.css"</c>, this full
	  name will be used to locate the file. If only the file name is specified
	  however, e.g. "categories.css", then the CSS file is assumed to be located
	  in the data directory, <c>data_dir</c>, of the suite. The latter usage is
	  recommended since it is portable compared to hard coding path names in the 
	  suite!</p>

	<p>The <c>Category</c> argument in the example above may have the
	  value (atom) <c>sys_config</c> (white on blue), <c>sys_state</c>
	  (black on yellow) or <c>error</c> (white on red).</p>
  </section>

  <section>
    <marker id="repeating_tests"></marker>
    <title>Repeating tests</title>    
    <p>You can order Common Test to repeat the tests you specify. You can choose
       to repeat tests a certain 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
       means of time, it is also possible to specify what action Common Test should 
       take upon timeout. Either Common Test performs all tests in the current run before stopping, 
       or it stops as soon as the current test job is finished. Repetition can be activated by
       means of <c>ct_run</c> start flags, or tuples in the <c>ct:run:test/1</c>
       option list argument. The flags (options in parenthesis) are:</p>
       <list>
       <item><c>-repeat N ({repeat,N})</c>, where <c>N</c> is a positive integer.</item>
       <item><c>-duration DurTime ({duration,DurTime})</c>, where <c>DurTime</c> is the duration, see below.</item>
       <item><c>-until StopTime ({until,StopTime})</c>, where <c>StopTime</c> is finish time, see below.</item>
       <item><c>-force_stop ({force_stop,true})</c></item>
       </list>
       <p>The duration time, <c>DurTime</c>, is specified as <c>HHMMSS</c>. Example: 
          <c>-duration 012030</c> or <c>{duration,"012030"}</c>, means the tests will 
	  be executed and (if time allows) repeated, until timeout occurs after 1 h, 20 min 
	  and 30 secs. 
	  <c>StopTime</c> can be specified as <c>HHMMSS</c> and is then interpreted as a time today 
	  (or possibly tomorrow). <c>StopTime</c> can also be specified as <c>YYMoMoDDHHMMSS</c>. 
	  Example: <c>-until 071001120000</c> or <c>{until,"071001120000"}</c>, which means the tests
	  will be executed and (if time allows) repeated, until 12 o'clock on the 1st of Oct 2007.</p>

       <p>When timeout occurs, Common Test will never abort the test run immediately, since 
          this might leave the system under test in an undefined, and possibly bad, state.
	  Instead Common Test will finish the current test job, or the complete test 
	  run, before stopping. The latter is the default behaviour. The <c>force_stop</c> 
	  flag/option tells Common Test to stop as soon as the current test job is finished.
	  Note that since Common Test always finishes off the current test job or test session,
	  the time specified with <c>duration</c> or <c>until</c> is never definitive!</p>

       <p>Log files from every single repeated test run is saved in normal Common Test fashion (see above). 
          Common Test may 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.</p>

       <p>Note that 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. There you can read
	  the repetition number, remaining time, etc.</p>

       <p>Example 1:</p>
       <pre>
          $ ct_run -dir $TEST_ROOT/to1 $TEST_ROOT/to2 -duration 001000 -force_stop</pre>
       <p>Here the suites in test directory to1, followed by the suites in to2, will be executed 
          in one test run. A timeout event will occur after 10 minutes. As long as there is time 
	  left, Common Test will repeat the test run (i.e. starting over with the to1 test). 
	  When the timeout occurs, Common Test will stop as soon as the current job is finished
	  (because of the <c>force_stop</c> flag). As a result, the specified test run might be 
	  aborted after the to1 test and before the to2 test.</p>

       <p>Example 2:</p>
       <pre>
          $ date
	  Fri Sep 28 15:00:00 MEST 2007

          $ ct_run -dir $TEST_ROOT/to1 $TEST_ROOT/to2 -until 160000</pre>
       <p>Here the same test run as in the example above will be executed (and possibly repeated). 
          In this example, however, the timeout will occur after 1 hour and when that happens,
	  Common Test will finish the entire test run before stopping (i.e. the to1 and to2 test
	  will always both be executed in the same test run).</p>
       
       <p>Example 3:</p>
       <pre>
          $ ct_run -dir $TEST_ROOT/to1 $TEST_ROOT/to2 -repeat 5</pre>
       <p>Here the test run, including both the to1 and the to2 test, will be repeated 5 times.</p>

       <note><p>This feature should not be confused with the <c>repeat</c> property of a test
          case group. The options described here are used to repeat execution of entire test runs,
	  while the <c>repeat</c> property of a test case group makes it possible to repeat
	  execution of sets of test cases within a suite. For more information about the latter,
	  see the <seealso marker="write_test_chapter#test_case_groups">Writing Test Suites</seealso>
	  chapter.</p></note>
  </section>

  <section>
    <marker id="silent_connections"></marker>
      <title>Silent Connections</title>
      <p>The protocol handling processes in Common Test, implemented by ct_telnet,
      ct_ssh, ct_ftp etc, do verbose printing to the test case logs. This can be switched off
      by means of the <c>-silent_connections</c> flag:</p>
      
      <pre>
	ct_run -silent_connections [conn_types]
      </pre>
      
      <p>where <c>conn_types</c> specifies <c>ssh, telnet, ftp, rpc</c> and/or <c>snmp</c>.</p>
      
      <p>Example:</p>
      
      <pre>
	ct_run ... -silent_connections ssh telnet</pre>
      <p>switches off logging for ssh and telnet connections.</p>
      
      <pre>
	ct_run ... -silent_connections</pre>
      <p>switches off logging for all connection types.</p>
      
      
      <p>Fatal communication error and reconnection attempts will always be printed even 
      if logging has been suppressed for the connection type in question. However, operations
      such as sending and receiving data will be performed silently.</p>
      
      <p>It is possible to also specify <c>silent_connections</c> in a test suite. This is
	accomplished by returning a tuple, <c>{silent_connections,ConnTypes}</c>, in the
	<c>suite/0</c> or test case info list. If <c>ConnTypes</c> is a list of atoms 
	(<c>ssh, telnet, ftp, rpc</c> and/or <c>snmp</c>), output for any corresponding connections 
	will be suppressed. Full logging is per default enabled for any connection of type not 
	specified in <c>ConnTypes</c>. Hence, if <c>ConnTypes</c> is the empty list, logging 
	is enabled for all connections.</p>
      
	<p>Example:</p>
      
      <pre>
	
	-module(my_SUITE).

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

	...

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

	my_testcase1(_) ->
	    ...

	my_testcase2(_) ->
	    ...
      </pre>
      
      <p>In this example, <c>suite/0</c> tells Common Test to suppress
	printouts from telnet and ssh connections. This is valid for
	all test cases. However, <c>my_testcase1/0</c> specifies that
	for this test case, only ssh should be silent. The result is
	that <c>my_testcase1</c> will get telnet info (if any) printed
	in the log, but not ssh info. <c>my_testcase2</c> will get no
	info from either connection printed.</p>
      
	<p><c>silent_connections</c> may also be specified with a term
	in a test specification
	(see <seealso marker="run_test_chapter#test_specifications">Test
	Specifications</seealso>). Connections provided with the
	<c>silent_connections</c> start	flag/option, will be merged with
	any connections listed in the test specification.</p>

	<p>The <c>silent_connections</c> start flag/option and test
	specification term, overrides any settings made by the info functions
	inside the test suite.</p>
      
      <note><p>Note that in the current Common Test version, the
	<c>silent_connections</c> feature only works for telnet
	and ssh connections! Support for other connection types will be added
	in future Common Test versions.</p></note>
      
  </section>
</chapter>