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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:post_groups(SuiteName, GroupDefs) -> NewGroupDefs
Types:
SuiteName = atom()
GroupDefs = NewGroupDefs = [Group]
Group = {GroupName,Properties,GroupsAndTestCases}
GroupName = atom()
Properties = [parallel | sequence | Shuffle | {GroupRepeatType,N}]
GroupsAndTestCases = [Group | {group,GroupName} | TestCase | {testcase,TestCase,TCRepeatProps}]
TestCase = atom()
TCRepeatProps = [{repeat,N} | {repeat_until_ok,N} | {repeat_until_fail,N}]
Shuffle = shuffle | {shuffle,Seed}
Seed = {integer(),integer(),integer()}
GroupRepeatType = repeat | repeat_until_all_ok | repeat_until_all_fail | repeat_until_any_ok |
repeat_until_any_fail
N = integer() | forever
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.
Note:
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
Types:
SuiteName = atom()
Return = NewReturn = Tests | {skip,Reason}
Tests = [TestCase | {testcase,TestCase,TCRepeatProps} | {group,GroupName} |
{group,GroupName,Properties} | {group,GroupName,Properties,SubGroups}]
TestCase = atom()
TCRepeatProps = [{repeat,N} | {repeat_until_ok,N} | {repeat_until_fail,N}]
GroupName = atom()
Properties = GroupProperties | default
SubGroups = [{GroupName,Properties} | {GroupName,Properties,SubGroups}]
Shuffle = shuffle | {shuffle,Seed}
Seed = {integer(),integer(),integer()}
GroupRepeatType = repeat | repeat_until_all_ok | repeat_until_all_fail | repeat_until_any_ok |
repeat_until_any_fail
N = integer() | forever
GroupDefs = NewGroupDefs = [Group]
Group = {GroupName,GroupProperties,GroupsAndTestCases}
GroupProperties = [parallel | sequence | Shuffle | {GroupRepeatType,N}]
GroupsAndTestCases = [Group | {group,GroupName} | TestCase]
Reason = term()
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.
Note:
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
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 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
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 function 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.