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NAME
ct_hooks - A callback interface on top of Common Test
DESCRIPTION
The Common Test Hook (henceforth called CTH) framework allows extensions of the default behaviour of
Common Test by means of callbacks before and after all test suite calls. It is meant for advanced users
of Common Test which want to abstract out behaviour which is common to multiple test suites.
In brief, Common Test Hooks allows you to:
* Manipulate the runtime config before each suite configuration call
* Manipulate the return of all suite configuration calls and in extension the result of the test
themselves.
The following sections describe the mandatory and optional CTH functions Common Test will call during
test execution. For more details see Common Test Hooks in the User's Guide.
For information about how to add a CTH to your suite see Installing a CTH in the User's Guide.
Note:
See the Example CTH in the User's Guide for a minimal example of a CTH.
CALLBACK FUNCTIONS
The following functions define the callback interface for a Common Test Hook.
EXPORTS
Module:init(Id, Opts) -> {ok, State} | {ok, State, Priority}
Types:
Id = reference() | term()
Opts = term()
State = term()
Priority = integer()
MANDATORY
Always called before any other callback function. Use this to initiate any common state. It should
return a state for this CTH.
Id is the return value of id/1, or a reference (created using make_ref/0) if id/1 is not
implemented.
Priority is the relative priority of this hook. Hooks with a lower priority will be executed
first. If no priority is given, it will be set to 0.
For details about when init is called see scope in the User's Guide.
Module:pre_init_per_suite(SuiteName, InitData, CTHState) -> Result
Types:
SuiteName = atom()
InitData = Config | SkipOrFail
Config = NewConfig = [{Key,Value}]
CTHState = NewCTHState = term()
Result = {Return, NewCTHState}
Return = NewConfig | SkipOrFail
SkipOrFail = {fail, Reason} | {skip, Reason}
Key = atom()
Value = term()
Reason = term()
OPTIONAL
This function is called before init_per_suite if it exists. It typically contains
initialization/logging which needs to be done before init_per_suite is called. If {skip,Reason} or
{fail,Reason} is returned, init_per_suite and all test cases of the suite will be skipped and
Reason printed in the overview log of the suite.
SuiteName is the name of the suite to be run.
InitData is the original config list of the test suite, or a SkipOrFail tuple if a previous CTH
has returned this.
CTHState is the current internal state of the CTH.
Return is the result of the init_per_suite function. If it is {skip,Reason} or {fail,Reason}
init_per_suite will never be called, instead the initiation is considered to be skipped/failed
respectively. If a NewConfig list is returned, init_per_suite will be called with that NewConfig
list. See Pre Hooks in the User's Guide for more details.
Note that this function is only called if the CTH has been added before init_per_suite is run, see
CTH Scoping in the User's Guide for details.
Module:post_init_per_suite(SuiteName, Config, Return, CTHState) -> Result
Types:
SuiteName = atom()
Config = [{Key,Value}]
Return = NewReturn = Config | SkipOrFail | term()
SkipOrFail = {fail, Reason} | {skip, Reason} | term()
CTHState = NewCTHState = term()
Result = {NewReturn, NewCTHState}
Key = atom()
Value = term()
Reason = term()
OPTIONAL
This function is called after init_per_suite if it exists. It typically contains extra checks to
make sure that all the correct dependencies have been started correctly.
Return is what init_per_suite returned, i.e. {fail,Reason}, {skip,Reason}, a Config list or a
term describing how init_per_suite failed.
NewReturn is the possibly modified return value of init_per_suite . It is here possible to recover
from a failure in init_per_suite by returning the ConfigList with the tc_status element removed.
See Post Hooks in the User's Guide for more details.
CTHState is the current internal state of the CTH.
Note that this function is only called if the CTH has been added before or in init_per_suite, see
CTH Scoping in the User's Guide for details.
Module:pre_init_per_group(GroupName, InitData, CTHState) -> Result
Types:
GroupName = atom()
InitData = Config | SkipOrFail
Config = NewConfig = [{Key,Value}]
CTHState = NewCTHState = term()
Result = {NewConfig | SkipOrFail, NewCTHState}
SkipOrFail = {fail,Reason} | {skip, Reason}
Key = atom()
Value = term()
Reason = term()
OPTIONAL
This function is called before init_per_group if it exists. It behaves the same way as
pre_init_per_suite, but for the init_per_group instead.
Module:post_init_per_group(GroupName, Config, Return, CTHState) -> Result
Types:
GroupName = atom()
Config = [{Key,Value}]
Return = NewReturn = Config | SkipOrFail | term()
SkipOrFail = {fail,Reason} | {skip, Reason}
CTHState = NewCTHState = term()
Result = {NewReturn, NewCTHState}
Key = atom()
Value = term()
Reason = term()
OPTIONAL
This function is called after init_per_group if it exists. It behaves the same way as
post_init_per_suite, but for the init_per_group instead.
Module:pre_init_per_testcase(TestcaseName, InitData, CTHState) -> Result
Types:
TestcaseName = atom()
InitData = Config | SkipOrFail
Config = NewConfig = [{Key,Value}]
CTHState = NewCTHState = term()
Result = {NewConfig | SkipOrFail, NewCTHState}
SkipOrFail = {fail,Reason} | {skip, Reason}
Key = atom()
Value = term()
Reason = term()
OPTIONAL
This function is called before init_per_testcase if it exists. It behaves the same way as
pre_init_per_suite, but for the init_per_testcase function instead.
Note that it is not possible to add CTH's here right now, that feature might be added later, but
it would right now break backwards compatibility.
Module:post_end_per_testcase(TestcaseName, Config, Return, CTHState) -> Result
Types:
TestcaseName = atom()
Config = [{Key,Value}]
Return = NewReturn = Config | SkipOrFail | term()
SkipOrFail = {fail,Reason} | {skip, Reason}
CTHState = NewCTHState = term()
Result = {NewReturn, NewCTHState}
Key = atom()
Value = term()
Reason = term()
OPTIONAL
This function is called after end_per_testcase if it exists. It behaves the same way as
post_init_per_suite, but for the end_per_testcase function instead.
Module:pre_end_per_group(GroupName, EndData, CTHState) -> Result
Types:
GroupName = atom()
EndData = Config | SkipOrFail
Config = NewConfig = [{Key,Value}]
CTHState = NewCTHState = term()
Result = {NewConfig | SkipOrFail, NewCTHState}
SkipOrFail = {fail,Reason} | {skip, Reason}
Key = atom()
Value = term()
Reason = term()
OPTIONAL
This function is called before end_per_group if it exists. It behaves the same way as
pre_init_per_suite, but for the end_per_group function instead.
Module:post_end_per_group(GroupName, Config, Return, CTHState) -> Result
Types:
GroupName = atom()
Config = [{Key,Value}]
Return = NewReturn = Config | SkipOrFail | term()
SkipOrFail = {fail,Reason} | {skip, Reason}
CTHState = NewCTHState = term()
Result = {NewReturn, NewCTHState}
Key = atom()
Value = term()
Reason = term()
OPTIONAL
This function is called after end_per_group if it exists. It behaves the same way as
post_init_per_suite, but for the end_per_group function instead.
Module:pre_end_per_suite(SuiteName, EndData, CTHState) -> Result
Types:
SuiteName = atom()
EndData = Config | SkipOrFail
Config = NewConfig = [{Key,Value}]
CTHState = NewCTHState = term()
Result = {NewConfig | SkipOrFail, NewCTHState}
SkipOrFail = {fail,Reason} | {skip, Reason}
Key = atom()
Value = term()
Reason = term()
OPTIONAL
This function is called before end_per_suite if it exists. It behaves the same way as
pre_init_per_suite, but for the end_per_suite function instead.
Module:post_end_per_suite(SuiteName, Config, Return, CTHState) -> Result
Types:
SuiteName = atom()
Config = [{Key,Value}]
Return = NewReturn = Config | SkipOrFail | term()
SkipOrFail = {fail,Reason} | {skip, Reason}
CTHState = NewCTHState = term()
Result = {NewReturn, NewCTHState}
Key = atom()
Value = term()
Reason = term()
OPTIONAL
This function is called after end_per_suite if it exists. It behaves the same way as
post_init_per_suite, but for the end_per_suite function instead.
Module:on_tc_fail(TestcaseName, Reason, CTHState) -> NewCTHState
Types:
TestcaseName = init_per_suite | end_per_suite | init_per_group | end_per_group | atom()
Reason = term()
CTHState = NewCTHState = term()
OPTIONAL
This function is called whenever a testcase fails. It is called after the post function has been
called for the testcase which failed. i.e. if init_per_suite fails this function is called after
post_init_per_suite, and if a testcase fails it is called after post_end_per_testcase.
The data which comes with the Reason follows the same format as the FailReason in the tc_done
event. See Event Handling in the User's Guide for details.
Module:on_tc_skip(TestcaseName, Reason, CTHState) -> NewCTHState
Types:
TestcaseName = end_per_suite | {init_per_group,GroupName} | {end_per_group,GroupName} | atom()
GroupName = atom()
Reason = {tc_auto_skip | tc_user_skip, term()}
CTHState = NewCTHState = term()
OPTIONAL
This function is called whenever a testcase is skipped. It is called after the post function has
been called for the testcase which was skipped. i.e. if init_per_group is skipped this function is
called after post_init_per_group , and if a testcase is skipped it is called after
post_end_per_testcase .
The data which comes with the Reason follows the same format as tc_auto_skip and tc_user_skip
events. See Event Handling in the User's Guide for details.
Module:terminate(CTHState)
Types:
CTHState = term()
OPTIONAL
This function is called at the end of a CTH's scope.
Module:id(Opts) -> Id
Types:
Opts = term()
Id = term()
OPTIONAL
The Id is used to uniquely identify a CTH instance, if two CTH's return the same Id the second CTH
is ignored and subsequent calls to the CTH will only be made to the first instance. For more
information see Installing a CTH in the User's Guide.
This function should NOT have any side effects as it might be called multiple times by Common
Test.
If not implemented the CTH will act as if this function returned a call to make_ref/0.