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NAME
ct_hooks - A callback interface on top of Common Test.
DESCRIPTION
The Common Test Hook (CTH) framework allows extensions of the default behavior of Common
Test by callbacks before and after all test suite calls. It is intended for advanced users
of Common Test who want to abstract out behavior that is common to multiple test suites.
In brief, CTH allows you to:
* Manipulate the runtime configuration before each suite configuration call.
* Manipulate the return of all suite configuration calls and by extension the result of
the test themselves.
The following sections describe the mandatory and optional CTH functions that Common Test
calls during test execution. For more details, see section Common Test Hooks in the User's
Guide.
For information about how to add a CTH to your suite, see section Installing a CTH in the
User's Guide.
Note:
For a minimal example of a CTH, see section Example CTH in the User's Guide.
CALLBACK FUNCTIONS
The following functions define the callback interface for a CTH.
EXPORTS
Module:init(Id, Opts) -> {ok, State} | {ok, State, Priority}
Types:
Id = reference() | term()
Opts = term()
State = term()
Priority = integer()
MANDATORY
This function is always called before any other callback function. Use it to
initiate any common state. It is to return a state for this CTH.
Id is either the return value of ct_hooks:id/1, or a reference (created using
erlang:make_ref/0 in ERTS) if ct_hooks:id/1 is not implemented.
Priority is the relative priority of this hook. Hooks with a lower priority are
executed first. If no priority is specified, it is set to 0.
For details about when init is called, see section CTH 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 that must 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 are 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 configuration 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 is never called, instead the initiation is considered
to be skipped or failed, respectively. If a NewConfig list is returned,
init_per_suite is called with that NewConfig list. For more details, see section
Pre Hooks in the User's Guide.
This function is called only if the CTH is added before init_per_suite is run. For
details, see section CTH Scope in the User's Guide.
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 ensure that all the correct dependencies are started correctly.
Return is what init_per_suite returned, that is, {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. To recover from
a failure in init_per_suite, return ConfigList with the tc_status element removed.
For more details, see Post Hooks in section "Manipulating Tests" in the User's
Guide.
CTHState is the current internal state of the CTH.
This function is called only if the CTH is added before or in init_per_suite. For
details, see section CTH Scope in the User's Guide.
Module:pre_init_per_group(SuiteName, GroupName, InitData, CTHState) -> Result
Types:
SuiteName = atom()
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 function init_per_group instead.
If Module:pre_init_per_group/4 is not exported, common_test will attempt to call
Module:pre_init_per_group(GroupName, InitData, CTHState) instead. This is for
backwards compatibility.
Module:post_init_per_group(SuiteName, GroupName, Config, Return, CTHState) -> Result
Types:
SuiteName = atom()
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 function init_per_group instead.
If Module:post_init_per_group/5 is not exported, common_test will attempt to call
Module:post_init_per_group(GroupName, Config, Return, CTHState) instead. This is
for backwards compatibility.
Module:pre_init_per_testcase(SuiteName, TestcaseName, InitData, CTHState) -> Result
Types:
SuiteName = atom()
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 function init_per_testcase instead.
If Module:pre_init_per_testcase/4 is not exported, common_test will attempt to call
Module:pre_init_per_testcase(TestcaseName, InitData, CTHState) instead. This is for
backwards compatibility.
CTHs cannot be added here right now. That feature may be added in a later release,
but it would right now break backwards compatibility.
Module:post_init_per_testcase(SuiteName, TestcaseName, Config, Return, CTHState) -> Result
Types:
SuiteName = atom()
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 init_per_testcase if it exists. It behaves the same
way as post_init_per_suite, but for function init_per_testcase instead.
If Module:post_init_per_testcase/5 is not exported, common_test will attempt to
call Module:post_init_per_testcase(TestcaseName, Config, Return, CTHState) instead.
This is for backwards compatibility.
Module:pre_end_per_testcase(SuiteName, TestcaseName, EndData, CTHState) -> Result
Types:
SuiteName = atom()
TestcaseName = atom()
EndData = Config
Config = NewConfig = [{Key,Value}]
CTHState = NewCTHState = term()
Result = {NewConfig, NewCTHState}
Key = atom()
Value = term()
Reason = term()
OPTIONAL
This function is called before end_per_testcase if it exists. It behaves the same
way as pre_end_per_suite, but for function end_per_testcase instead.
This function can not change the result of the test case by returning skip or fail
tuples, but it may insert items in Config that can be read in end_per_testcase/2 or
in post_end_per_testcase/5.
If Module:pre_end_per_testcase/4 is not exported, common_test will attempt to call
Module:pre_end_per_testcase(TestcaseName, EndData, CTHState) instead. This is for
backwards compatibility.
Module:post_end_per_testcase(SuiteName, TestcaseName, Config, Return, CTHState) -> Result
Types:
SuiteName = atom()
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_end_per_suite, but for function end_per_testcase instead.
If Module:post_end_per_testcase/5 is not exported, common_test will attempt to call
Module:post_end_per_testcase(TestcaseName, Config, Return, CTHState) instead. This
is for backwards compatibility.
Module:pre_end_per_group(SuiteName, GroupName, EndData, CTHState) -> Result
Types:
SuiteName = atom()
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 function end_per_group instead.
If Module:pre_end_per_group/4 is not exported, common_test will attempt to call
Module:pre_end_per_group(GroupName, EndData, CTHState) instead. This is for
backwards compatibility.
Module:post_end_per_group(SuiteName, GroupName, Config, Return, CTHState) -> Result
Types:
SuiteName = atom()
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 function end_per_group instead.
If Module:post_end_per_group/5 is not exported, common_test will attempt to call
Module:post_end_per_group(GroupName, Config, Return, CTHState) instead. This is for
backwards compatibility.
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 function end_per_suite 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 function end_per_suite instead.
Module:on_tc_fail(SuiteName, TestName, Reason, CTHState) -> NewCTHState
Types:
SuiteName = atom()
TestName = init_per_suite | end_per_suite | {init_per_group,GroupName} |
{end_per_group,GroupName} | {FuncName,GroupName} | FuncName
FuncName = atom()
GroupName = atom()
Reason = term()
CTHState = NewCTHState = term()
OPTIONAL
This function is called whenever a test case (or configuration function) fails. It
is called after the post function is called for the failed test case, that is:
* If init_per_suite fails, this function is called after post_init_per_suite.
* If a test case fails, this funcion is called after post_end_per_testcase.
If the failed test case belongs to a test case group, the first argument is a tuple
{FuncName,GroupName}, otherwise only the function name.
The data that comes with Reason follows the same format as FailReason in event
tc_done. For details, see section Event Handling in the User's Guide.
If Module:on_tc_fail/4 is not exported, common_test will attempt to call
Module:on_tc_fail(TestName, Reason, CTHState) instead. This is for backwards
compatibility.
Module:on_tc_skip(SuiteName, TestName, Reason, CTHState) -> NewCTHState
Types:
SuiteName = atom()
TestName = init_per_suite | end_per_suite | {init_per_group,GroupName} |
{end_per_group,GroupName} | {FuncName,GroupName} | FuncName
FuncName = atom()
GroupName = atom()
Reason = {tc_auto_skip | tc_user_skip, term()}
CTHState = NewCTHState = term()
OPTIONAL
This function is called whenever a test case (or configuration function) is
skipped. It is called after the post function is called for the skipped test case,
that is:
* If init_per_group is skipped, this function is called after
post_init_per_group.
* If a test case is skipped, this function is called after post_end_per_testcase.
If the skipped test case belongs to a test case group, the first argument is a
tuple {FuncName,GroupName}, otherwise only the function name.
The data that comes with Reason follows the same format as events tc_auto_skip and
tc_user_skip For details, see section Event Handling in the User's Guide.
If Module:on_tc_skip/4 is not exported, common_test will attempt to call
Module:on_tc_skip(TestName, Reason, CTHState) instead. This is for backwards
compatibility.
Module:terminate(CTHState)
Types:
CTHState = term()
OPTIONAL
This function is called at the end of a CTH scope.
Module:id(Opts) -> Id
Types:
Opts = term()
Id = term()
OPTIONAL
The Id identifies a CTH instance uniquely. If two CTHs return the same Id, the
second CTH is ignored and subsequent calls to the CTH are only made to the first
instance. For details, see section Installing a CTH in the User's Guide.
This function is not to have any side effects, as it can be called multiple times
by Common Test.
If not implemented, the CTH acts as if this function returned a call to make_ref/0.