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

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<erlref>
  <header>
    <copyright>
      <year>2003</year><year>2016</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      Licensed under the Apache License, Version 2.0 (the "License");
      you may not use this file except in compliance with the License.
      You may obtain a copy of the License at
 
          http://www.apache.org/licenses/LICENSE-2.0

      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      See the License for the specific language governing permissions and
      limitations under the License.

    </legalnotice>

    <title>Common Test</title>
    <prepared>Kenneth Lundin, Peter Andersson</prepared>
    <responsible>Peter Andersson</responsible>
    <docno></docno>
    <approved></approved>
    <checked></checked>
    <date>2003-10-21</date>
    <rev>PA1</rev>
    <file>common_test_app.sgml</file>
  </header>
  <module>common_test</module> 
  <modulesummary>A framework for automated testing of any target nodes.</modulesummary>

  <description>

    <p>The <c>Common Test</c> framework is an environment for
      implementing and performing automatic and semi-automatic execution of
      test cases.</p>

    <p>In brief, <c>Common Test</c> supports:</p>

    <list>
      <item>Automated execution of test suites (sets of test cases)</item>
      <item>Logging of events during execution</item>
      <item>HTML presentation of test suite results</item>
      <item>HTML presentation of test suite code</item>
      <item>Support functions for test suite authors</item>
      <item>Step-by-step execution of test cases</item>
    </list>

    <p>The following section describes the mandatory and optional test suite
      functions that <c>Common Test</c> calls during test execution.
      For more details, see section
      <seealso marker="write_test_chapter">Writing Test Suites</seealso>
      in the User's Guide.</p>

  </description>

  <section>
    <title>Test Case Callback Functions</title>
    <p>The following functions define the callback interface
      for a test suite.</p>
  </section>

  <funcs>
    <func>
      <name>Module:all() -> Tests | {skip,Reason} </name>
      <fsummary>Returns the list of all test case groups and test cases
	in the module.</fsummary>
      <type>
	<v>Tests = [TestCase | {group,GroupName} | {group,GroupName,Properties} | {group,GroupName,Properties,SubGroups}]</v>
	<v>TestCase = atom()</v>
	<v>GroupName = atom()</v>
	<v>Properties = [parallel | sequence | Shuffle | {RepeatType,N}] | default</v>
	<v>SubGroups = [{GroupName,Properties} | {GroupName,Properties,SubGroups}]</v>
	<v>Shuffle = shuffle | {shuffle,Seed}</v>
	<v>Seed = {integer(),integer(),integer()}</v>
	<v>RepeatType = repeat | repeat_until_all_ok | repeat_until_all_fail | repeat_until_any_ok | repeat_until_any_fail</v>
	<v>N = integer() | forever</v>
	<v>Reason = term()</v>
      </type>

      <desc>	
	<p>MANDATORY</p>

	<p>Returns the list of all test cases and test case groups in the
          test suite module to be executed. This list also specifies the
          order the cases and groups are executed by <c>Common Test</c>.
          A test case is represented by an atom,
	  the name of the test case function. A test case group is
	  represented by a <c>group</c> tuple, where <c>GroupName</c>,
	  an atom, is the name of the group (defined in
	  <seealso marker="#Module:groups-0"><c>groups/0</c></seealso>).
	  Execution properties for groups can also be specified, both
	  for a top-level group and for any of its subgroups.
	  Group execution properties specified here override
	  properties in the group definition (see
	  <seealso marker="#Module:groups-0"><c>groups/0</c></seealso>).
	  (With value <c>default</c>, the group definition properties
	  are used).</p>

	<p>If <c>{skip,Reason}</c> is returned, all test cases
          in the module are skipped and <c>Reason</c>
          is printed on the HTML result page.</p>

	<p>For details on groups, see section
	  <seealso marker="write_test_chapter#test_case_groups">Test Case
	  Groups</seealso> in the User's Guide.</p>

    </desc>
    </func>

    <func>
      <name>Module:groups() -> GroupDefs</name>
      <fsummary>Returns a list of test case group definitions.</fsummary>
      <type>
        <v>GroupDefs = [Group]</v>
        <v>Group = {GroupName,Properties,GroupsAndTestCases}</v>
        <v>GroupName = atom()</v>
        <v>Properties = [parallel | sequence | Shuffle | {RepeatType,N}]</v>
        <v>GroupsAndTestCases = [Group | {group,GroupName} | TestCase]</v>
        <v>TestCase = atom()</v>
        <v>Shuffle = shuffle | {shuffle,Seed}</v>
        <v>Seed = {integer(),integer(),integer()}</v>
        <v>RepeatType = repeat | repeat_until_all_ok | repeat_until_all_fail | repeat_until_any_ok | repeat_until_any_fail</v>
        <v>N = integer() | forever</v>
      </type>

      <desc>	
	<p>OPTIONAL</p>

	<p>Defines test case groups. For details, see section
	  <seealso marker="write_test_chapter#test_case_groups">Test Case 
	  Groups</seealso> in the User's Guide.</p>      
      </desc>
    </func>

      <func>
	<name>Module:suite() -> [Info] </name>
	<fsummary>Test suite info function (providing default data
	  for the suite).</fsummary>
	<type>
	  <v>Info = {timetrap,Time} | {require,Required} | {require,Name,Required} | {userdata,UserData} | {silent_connections,Conns} | {stylesheet,CSSFile} | {ct_hooks, CTHs}</v>
	  <v>Time = TimeVal | TimeFunc</v>
	  <v>TimeVal = MilliSec | {seconds,integer()} | {minutes,integer()} | {hours,integer()}</v>
	  <v>TimeFunc = {Mod,Func,Args} | Fun</v>
	  <v>MilliSec = integer()</v>
	  <v>Mod = atom()</v>
	  <v>Func = atom()</v>
	  <v>Args = list()</v>
	  <v>Fun = fun()</v>
	  <v>Required = Key | {Key,SubKeys} | {Key,SubKey} | {Key,SubKey,SubKeys}</v>
	  <v>Key = atom()</v>
	  <v>SubKeys = SubKey | [SubKey]</v>
	  <v>SubKey = atom()</v>
	  <v>Name = atom()</v>
	  <v>UserData = term()</v>
	  <v>Conns = [atom()]</v>
	  <v>CSSFile = string()</v>
	  <v>CTHs = [CTHModule |</v>
	  <v>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{CTHModule, CTHInitArgs} |</v>
	  <v>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{CTHModule, CTHInitArgs, CTHPriority}]</v>
	  <v>CTHModule = atom()</v>
	  <v>CTHInitArgs = term()</v>
	</type>
	<desc>	

        <p>OPTIONAL</p>

	<p>The test suite information function.	Returns a list of tagged
          tuples specifying various properties related to the execution of
          this test suite (common for all test cases in the suite).</p>

	<p>Tag <c>timetrap</c> sets the maximum time that each
	  test case is allowed to execute (including
	  <seealso marker="#Module:init_per_testcase-2"><c>init_per_testcase/2</c></seealso>
	  and
	  <seealso marker="#Module:end_per_testcase-2"><c>end_per_testcase/2</c></seealso>).
	  If the timetrap time is exceeded, the test case fails with reason
	  <c>timetrap_timeout</c>. A <c>TimeFunc</c> function can be used to
	  set a new timetrap by returning a <c>TimeVal</c>. It can also be
	  used to trigger a timetrap time-out by, at some point, returning a
	  value other than a <c>TimeVal</c>. For details, see section
	  <seealso marker="write_test_chapter#timetraps">Timetrap Time-Outs</seealso>
	  in the User's Guide.</p>

	<p>Tag <c>require</c> specifies configuration variables
	  required by test cases (or configuration functions)
	  in the suite. If the required configuration variables are not found
	  in any of the configuration files, all test cases are skipped.
	  For details about the <c>require</c> functionality, see funtion
	  <seealso marker="ct#require-1"><c>ct:require/1,2</c></seealso>.</p>

	<p>With <c>userdata</c>, the user can
	  specify any test suite-related information, which can be
	  read by calling
	  <seealso marker="ct#userdata-2"><c>ct:userdata/2</c></seealso>.</p>

	<p>Tag <c>ct_hooks</c> specifies the
	  <seealso marker="ct_hooks_chapter">Common Test Hooks</seealso>
	  to be run with this suite.</p>

	<p>Other tuples than the ones defined are ignored.</p>

	<p>For details about the test suite information function, see section
	  <seealso marker="write_test_chapter#suite">Test
	  Suite Information Function</seealso> in the User's Guide.</p>
    </desc>      
    </func>

      <func>
	<name>Module:init_per_suite(Config) -> NewConfig | {skip,Reason} |
	  {skip_and_save,Reason,SaveConfig}</name>
	<fsummary>Test suite initializations.</fsummary>
	<type>
	  <v>Config = NewConfig = SaveConfig = [{Key,Value}]</v>
	  <v>Key = atom()</v>
	  <v>Value = term()</v>
	  <v>Reason = term()</v>
	</type>
	<desc>	

	  <p>OPTIONAL; if this function is defined, then <seealso
	  marker="#Module:end_per_suite-1"><c>end_per_suite/1</c></seealso>
	  must also be defined.</p>

	  <p>This configuration function is called as the first function in the
	  suite. It typically contains initializations that are common for
	  all test cases in the suite, and that must only be done
	  once. Parameter <c>Config</c> is the configuration data
	  that can be modified. Whatever is returned from this
	  function is specified as <c>Config</c> to all configuration functions
	  and test cases in the suite.</p>

	  <p>If <c>{skip,Reason}</c>
	  is returned, all test cases in the suite are skipped
	  and <c>Reason</c> is printed in the overview log for the suite.</p>

	  <p>For information on <c>save_config</c> and <c>skip_and_save</c>,
	  see section
	  <seealso marker="dependencies_chapter#save_config">Saving
	  Configuration Data</seealso> in the User's Guide.</p>
    </desc>
    </func>

    <func>
      <name>Module:end_per_suite(Config) -> term() | 
	{save_config,SaveConfig}</name>
      <fsummary>Test suite finalization.</fsummary>
      <type>
	<v>Config = SaveConfig = [{Key,Value}]</v>
	<v>Key = atom()</v>
	<v>Value = term()</v>
      </type>

      <desc>	
	<p>OPTIONAL; if this function is defined, then <seealso
	  marker="#Module:init_per_suite-1"><c>init_per_suite/1</c></seealso>
	  must also be defined.</p>
	
	<p>This function is called as the last test case in the
	  suite. It is meant to be used for cleaning up after
	  <seealso marker="#Module:init_per_suite-1"><c>init_per_suite/1</c></seealso>.</p>
	<p>For information on <c>save_config</c>, see section
	  <seealso marker="dependencies_chapter#save_config">Saving
	  Configuration Data</seealso> in the User's Guide.</p>
      </desc>
    </func>

    <func>
      <name>Module:group(GroupName) -> [Info] </name>
      <fsummary>Test case group information function (providing default data
        for a test case group, that is, its test cases and
        subgroups).</fsummary>
      <type>
	<v>Info = {timetrap,Time} | {require,Required} | {require,Name,Required} | {userdata,UserData} | {silent_connections,Conns} | {stylesheet,CSSFile} | {ct_hooks, CTHs}</v>
	<v>Time = TimeVal | TimeFunc</v>
	<v>TimeVal = MilliSec | {seconds,integer()} | {minutes,integer()} | {hours,integer()}</v>
	<v>TimeFunc = {Mod,Func,Args} | Fun</v>
	<v>MilliSec = integer()</v>
	<v>Mod = atom()</v>
	<v>Func = atom()</v>
	<v>Args = list()</v>
	<v>Fun = fun()</v>
	<v>Required = Key | {Key,SubKeys} | {Key,Subkey} | {Key,Subkey,SubKeys}</v>
	<v>Key = atom()</v>
	<v>SubKeys = SubKey | [SubKey]</v>
	<v>SubKey = atom()</v>
	<v>Name = atom()</v>
	<v>UserData = term()</v>
	<v>Conns = [atom()]</v>
	<v>CSSFile = string()</v>
	<v>CTHs = [CTHModule |</v>
	<v>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{CTHModule, CTHInitArgs} |</v>
	<v>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{CTHModule, CTHInitArgs, CTHPriority}]</v>
	<v>CTHModule = atom()</v>
	<v>CTHInitArgs = term()</v>
      </type>
      <desc>	

	<p>OPTIONAL</p>

	<p>The test case group information function. It is supposed to
	  return a list of tagged tuples that specify various properties
	  related to the execution of a test case group (that is, its test
	  cases and subgroups). Properties set by
	  <seealso marker="#Module:group-1"><c>group/1</c></seealso> override
	  properties with the same key that have been set previously by
	  <seealso marker="#Module:suite-0"><c>suite/0</c></seealso>.</p>
	  
	<p>Tag <c>timetrap</c> sets the maximum time that each
	  test case is allowed to execute (including
	  <seealso marker="#Module:init_per_testcase-2"><c>init_per_testcase/2</c></seealso>
	  and
	  <seealso marker="#Module:end_per_testcase-2"><c>end_per_testcase/2</c></seealso>).
	  If the timetrap time is
	  exceeded, the test case fails with reason
	  <c>timetrap_timeout</c>. A <c>TimeFunc</c> function can be used to
	  set a new timetrap by returning a <c>TimeVal</c>. It can also be
	  used to trigger a timetrap time-out by, at some point, returning a
	  value other than a <c>TimeVal</c>. For details, see section
	  <seealso marker="write_test_chapter#timetraps">Timetrap
	  Time-Outs</seealso> in the User's Guide.</p>
	
	<p>Tag <c>require</c> specifies configuration variables
	  required by test cases (or configuration functions)
	  in the suite. If the required configuration variables are not found
	  in any of the configuration files, all test cases in this group are
	  skipped. For details about the <c>require</c> functionality, see
	  function
	  <seealso marker="ct#require-1"><c>ct:require/1,2</c></seealso>.</p>

	<p>With <c>userdata</c>, the user can
	  specify any test case group related information that can be 
	  read by calling
	  <seealso marker="ct#userdata-2"><c>ct:userdata/2</c></seealso>.</p>

	<p>Tag <c>ct_hooks</c> specifies the
	  <seealso marker="ct_hooks_chapter">Common Test Hooks</seealso>
	  to be run with this suite.</p>

	<p>Other tuples than the ones defined are ignored.</p>

	<p>For details about the test case group information function,
	  see section <seealso marker="write_test_chapter#group_info">Group
	  Information Function</seealso> in the User's Guide.</p>
    </desc>      
    </func>

      <func>
	<name>Module:init_per_group(GroupName, Config) -> NewConfig |
	  {skip,Reason}</name>
	<fsummary>Test case group initializations.</fsummary>
	<type>
	  <v>GroupName = atom()</v>
	  <v>Config = NewConfig = [{Key,Value}]</v>
	  <v>Key = atom()</v>
	  <v>Value = term()</v>
	  <v>Reason = term()</v>
	</type>
	<desc>	

	  <p>OPTIONAL; if this function is defined, then <seealso
	    marker="#Module:end_per_group-2"><c>end_per_group/2</c></seealso>
	    must also be defined.</p>

	  <p>This configuration function is called before execution of a
	    test case group. It typically contains initializations that are 
	    common for all test cases and subgroups in the group, and that
	    must only be performed once. <c>GroupName</c> is the name of the
	    group, as specified in the group definition (see
	    <seealso marker="#Module:groups-0"><c>groups/0</c></seealso>).
	    Parameter <c>Config</c> is the configuration data that can be
	    modified.
	    The return value of this function is given as <c>Config</c>
	    to all test cases and subgroups in the group.</p>

	  <p>If <c>{skip,Reason}</c>
	    is returned, all test cases in the group are skipped and
	    <c>Reason</c> is printed in the overview log for the group.</p>

	  <p>For information about test case groups, see section 
	    <seealso marker="write_test_chapter#test_case_groups">Test Case 
	    Groups</seealso> in the User's Guide.</p> 
    </desc>      
    </func>

      <func>
	<name>Module:end_per_group(GroupName, Config) -> term() |
	  {return_group_result,Status}</name>
	<fsummary>Test case group finalization.</fsummary>
	<type>
	  <v>GroupName = atom()</v>
	  <v>Config = [{Key,Value}]</v>
	  <v>Key = atom()</v>
	  <v>Value = term()</v>
	  <v>Status = ok | skipped | failed</v>
	</type>

	<desc>	
	  <p>OPTIONAL; if this function is defined, then <seealso
	    marker="#Module:init_per_group-2"><c>init_per_group/2</c></seealso>
	    must also be defined.</p>

	  <p>This function is called after the execution of a test case group
	    is finished. It is meant to be used for cleaning up after
	    <seealso marker="#Module:init_per_group-2"><c>init_per_group/2</c></seealso>.
	    A status value for a nested subgroup can be returned with
	    <c>{return_group_result,Status}</c>. The status can be retrieved in
	    <seealso marker="#Module:end_per_group-2"><c>end_per_group/2</c></seealso>
	    for the group on the level above. The status is also used by
	    <c>Common Test</c> for deciding if execution of a group is to
	    proceed if property <c>sequence</c> or <c>repeat_until_*</c>
	    is set.</p>

	  <p>For details about test case groups, see section 
	    <seealso marker="write_test_chapter#test_case_groups">Test Case
	    Groups</seealso> in the User's Guide.</p> 
       </desc>
    </func>

      <func>
	<name>Module:init_per_testcase(TestCase, Config) -> NewConfig | {fail,Reason} | {skip,Reason}</name>
	<fsummary>Test case initializations.</fsummary>
	<type>
	  <v> TestCase = atom()</v>
	  <v> Config = NewConfig = [{Key,Value}]</v>
	  <v> Key = atom()</v>
	  <v> Value = term()</v>
	  <v> Reason = term()</v>
	</type>
	<desc>

	  <p>OPTIONAL; if this function is defined,
	    then <seealso marker="#Module:end_per_testcase-2">
	      <c>end_per_testcase/2</c></seealso> must also be
	    defined.</p>

	  <p>This function is called before each test case. Argument
	  <c>TestCase</c> is the test case name, and
	  <c>Config</c> (list of key-value tuples) is the configuration
	  data that can be modified. The <c>NewConfig</c> list returned
	  from this function is given as <c>Config</c> to the test case.
	  If <c>{fail,Reason}</c> is returned, the test case is
	  marked as failed without being executed.</p>

	  <p>If <c>{skip,Reason}</c> is returned, the test case is skipped
	    and <c>Reason</c> is printed in the overview log for the suite.</p>
    </desc>
    </func>

      <func>
	<name>Module:end_per_testcase(TestCase, Config) -> term() | {fail,Reason} | {save_config,SaveConfig}</name>
	<fsummary>Test case finalization.</fsummary>
	<type>
	  <v>TestCase = atom()</v>
	  <v>Config = SaveConfig = [{Key,Value}]</v>
	  <v>Key = atom()</v>
	  <v>Value = term()</v>
	  <v>Reason = term()</v>
	</type>
	<desc>	

	  <p>OPTIONAL; if this function is defined,
	    then <seealso marker="#Module:init_per_testcase-2">
	      <c>init_per_testcase/2</c></seealso> must also be
	    defined.</p>

	  <p>This function is called after each test case, and can be used
	    to clean up after
	    <seealso marker="#Module:init_per_testcase-2"><c>init_per_testcase/2</c></seealso>
	    and the test case. Any return value (besides <c>{fail,Reason}</c>
	    and <c>{save_config,SaveConfig}</c>) is ignored. By returning
	    <c>{fail,Reason}</c>, <c>TestCase</c> is marked as faulty (even
	    though it was successful in the sense that it returned
	    a value instead of terminating).</p>

	<p>For information on <c>save_config</c>, see section
	  <seealso marker="dependencies_chapter#save_config">Saving
	  Configuration Data</seealso> in the User's Guide.</p>
	</desc>
      </func>

    <func>
      <name>Module:Testcase() -> [Info] </name>
      <fsummary>Test case information function.</fsummary>
      <type>
	<v>Info = {timetrap,Time} | {require,Required} | {require,Name,Required} | {userdata,UserData} | {silent_connections,Conns}</v>
	<v>Time = TimeVal | TimeFunc</v>
	<v>TimeVal = MilliSec | {seconds,integer()} | {minutes,integer()} | {hours,integer()}</v>
	<v>TimeFunc = {Mod,Func,Args} | Fun</v>
	<v>MilliSec = integer()</v>
	<v>Mod = atom()</v>
	<v>Func = atom()</v>
	<v>Args = list()</v>
	<v>Fun = fun()</v>
	<v>Required = Key | {Key,SubKeys} | {Key,Subkey} | {Key,Subkey,SubKeys}</v>
	<v>Key = atom()</v>
	<v>SubKeys = SubKey | [SubKey]</v>
	<v>SubKey = atom()</v>
	<v>Name = atom()</v>
	<v>UserData = term()</v>
	<v>Conns = [atom()]</v>
      </type>

      <desc>
	
	<p>OPTIONAL</p>

	<p>The test case information function. It is supposed to
	  return a list of tagged tuples that specify various properties
	  related to the execution of this particular test case.
	  Properties set by
	  <seealso marker="#Module:Testcase-0"><c>Testcase/0</c></seealso>
	  override properties set previously for the test case by
	  <seealso marker="#Module:group-1"><c>group/1</c></seealso> or
	  <seealso marker="#Module:suite-0"><c>suite/0</c></seealso>.</p>

	<p>Tag <c>timetrap</c> sets the maximum time that the
	  test case is allowed to execute. If the timetrap time is
	  exceeded, the test case fails with reason <c>timetrap_timeout</c>.
	  <seealso marker="#Module:init_per_testcase-2"><c>init_per_testcase/2</c></seealso>
	  and
	  <seealso marker="#Module:end_per_testcase-2"><c>end_per_testcase/2</c></seealso>
	  are included in the timetrap time.
	  A <c>TimeFunc</c> function can be used to
	  set a new timetrap by returning a <c>TimeVal</c>. It can also be
	  used to trigger a timetrap time-out by, at some point, returning a
	  value other than a <c>TimeVal</c>. For details, see section
	  <seealso marker="write_test_chapter#timetraps">Timetrap
	  Time-Outs</seealso> in the User's Guide.</p>
	
	<p>Tag <c>require</c> specifies configuration variables
	  that are required by the test case (or <c>init_per_testcase/2</c>
	  or <c>end_per_testcase/2</c>).
	  If the required configuration variables are not found in any of the
	  configuration files, the test case is skipped. For details about
	  the <c>require</c> functionality, see function
	  <seealso marker="ct#require-1"><c>ct:require/1,2</c></seealso>.</p>

	<p>If <c>timetrap</c> or <c>require</c> is not set, the
	  default values specified by
	  <seealso marker="#Module:suite-0"><c>suite/0</c></seealso> (or
	  <seealso marker="#Module:group-1"><c>group/1</c></seealso>) are used.</p>

	<p>With <c>userdata</c>, the user can specify any test case-related
	  information that can be read by calling
	  <seealso marker="ct#userdata-3"><c>ct:userdata/3</c></seealso>.</p>

	<p>Other tuples than the ones defined are ignored.</p>

	<p>For details about the test case information function, see section
	  <seealso marker="write_test_chapter#info_function">Test
	  Case Information Function</seealso> in the User's Guide.</p>
      </desc>
    </func>

    <func>
	<name>Module:Testcase(Config) ->  term() | {skip,Reason} | {comment,Comment} | {save_config,SaveConfig} | {skip_and_save,Reason,SaveConfig} | exit() </name>
      <fsummary>A test case.</fsummary>
      <type>
	<v>Config = SaveConfig = [{Key,Value}]</v>
	<v>Key = atom()</v>
	<v>Value = term()</v>
	<v>Reason = term()</v>
	<v>Comment = string()</v>
      </type>

      <desc>	  
	<p>MANDATORY</p>

	<p>The implementation of a test case. Call the functions to test and
	  check the result. If something fails, ensure the
	  function causes a runtime error or call
	  <seealso marker="ct#fail-1"><c>ct:fail/1,2</c></seealso>
	  (which also causes the test case process to terminate).</p>

	<p>Elements from the <c>Config</c> list can, for example, be read
	  with <c>proplists:get_value/2</c> in STDLIB
	  (or the macro <c>?config</c> defined in <c>ct.hrl</c>).</p>

	<p>If you decide not to run the test case after all, return
	  <c>{skip,Reason}</c>. <c>Reason</c> is then
	  printed in field <c>Comment</c> on the HTML result page.</p>

	<p>To print some information in field <c>Comment</c> on the HTML
	  result page, return <c>{comment,Comment}</c>.</p>

	<p>If the function returns anything else, the test case is
	  considered successful. The return value always gets printed
	  in the test case log file.</p>

	<p>For details about test case implementation, see section
	  <seealso marker="write_test_chapter#test_cases">Test Cases</seealso>
	  in the User's Guide.</p>

	<p>For information on <c>save_config</c> and <c>skip_and_save</c>,
	  see section
	  <seealso marker="dependencies_chapter#save_config">Saving
	  Configuration Data</seealso> in the User's Guide.</p>
      </desc>
    </func>

  </funcs>

</erlref>