ct_hooks
A callback interface on top of Common Test
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.
Functions
Module:init(Id, Opts) -> {ok, State} | {ok, State, Priority}
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, Config, CTHState) -> Result
SuiteName = atom()
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.
Config
is the original config list of the test suite.
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
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, Config, CTHState) -> Result
GroupName = atom()
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
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, Config, CTHState) -> Result
TestcaseName = atom()
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
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, Config, CTHState) -> Result
GroupName = atom()
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
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, Config, CTHState) -> Result
SuiteName = atom()
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
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
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
TestcaseName = end_per_suite | init_per_group | end_per_group | 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)
CTHState = term()
OPTIONAL
This function is called at the end of a CTH's scope.
Module:id(Opts) -> Id
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
.