Module
ct_hooks
Module Summary
A callback interface on top of Common Test.
Since
Module ct_hooks was introduced in OTP R14B02.
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.
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} | OTP R14B02 |
Types
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:post_groups(SuiteName, GroupDefs) -> NewGroupDefs | OTP 21.3.8 |
Types
OPTIONAL
This function is called after groups/0
. It is used to modify the test group definitions, for instance to add or remove groups or change group properties.
GroupDefs
is what groups/0
returned, that is, a list of group definitions.
NewGroupDefs
is the possibly modified version of this list.
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.
Notice that for CTHs that are installed by means of the suite/0
function, post_groups/2
is called before the init/2
hook function. However, for CTHs that are installed by means of the CT start flag, the init/2
function is called first.
Prior to each test execution, Common Test does a simulated test run in order to count test suites, groups and cases for logging purposes. This causes the post_groups/2
hook function to always be called twice. For this reason, side effects are best avoided in this callback.
Module:post_all(SuiteName, Return, GroupDefs) -> NewReturn | OTP 21.3.8 |
Types
OPTIONAL
This function is called after all/0
. It is used to modify the set of test cases and test group to be executed, for instance to add or remove test cases and groups, change group properties, or even skip all tests in the suite.
Return
is what all/0
returned, that is, a list of test cases and groups to be executed, or a tuple {skip,Reason}
.
GroupDefs
is what groups/0
or the post_groups/2
hook returned, that is, a list of group definitions.
NewReturn
is the possibly modified version of Return
.
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.
Notice that for CTHs that are installed by means of the suite/0
function, post_all/2
is called before the init/2
hook function. However, for CTHs that are installed by means of the CT start flag, the init/2
function is called first.
Prior to each test execution, Common Test does a simulated test run in order to count test suites, groups and cases for logging purposes. This causes the post_all/3
hook function to always be called twice. For this reason, side effects are best avoided in this callback.
Module:pre_init_per_suite(SuiteName, InitData, CTHState) -> Result | OTP R14B02 |
Types
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 | OTP R14B02 |
Types
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 | OTP 19.3 |
Types
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 | OTP 19.3 |
Types
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 | OTP 19.3 |
Types
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 | OTP 19.3 |
Types
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 | OTP 19.3 |
Types
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 cannot 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 | OTP 19.3 |
Types
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 | OTP 19.3 |
Types
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 | OTP 19.3 |
Types
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 | OTP R14B02 |
Types
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 | OTP R14B02 |
Types
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 | OTP 19.3 |
Types
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 afterpost_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 | OTP 19.3 |
Types
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 afterpost_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) | OTP R14B02 |
Module:id(Opts) -> Id | OTP R14B02 |
Types
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
.
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Licensed under the Apache License, Version 2.0.