Namers
The Purpose of Namers
Approvals::verify(text);
could be written as:
REQUIRE(text == (loadContentsFromFile("FileName.TestName.approved.txt"));
Part of Approval Tests’ “Convention over Configuration” is to remove this by automatically creating meaningful file names, and therefore it could be written as:
REQUIRE(text == (loadContentsFromFile(namer.getApprovedFile()));
“If you always have to do something, you should never have to do something.”
Since all of your REQUIRE
s would look like this, we can simplify
it with the above Approvals::verify(text);
- and this is enabled by
the ApprovalNamers.
The Parts of Namers
The conventional layout for files saved with Approvals::verify()
and
related functions is:
path_to_test_file/FileName.TestName.approved.txt
path_to_test_file/FileName.TestName.received.txt
The Approval Namer is responsible for creating these two names.
The interface for this is ApprovalNamer.
Converting Test Names to Valid FileNames
Some C++ test frameworks allow test names to contain characters that are not valid in file or directory names on every operating system.
Therefore, by default, ApprovalTests will convert any non-valid filename
character to an _
(underscore). This can mean "test <"
and
"test >"
would produce colliding test__.approved.txt
.
This behavior is customizable, here’s an example:
TEST_CASE("Sanitizer <3 fileNames")
{
{
auto disposer =
ApprovalTests::Approvals::useFileNameSanitizer([](std::string incoming) {
return ApprovalTests::StringUtils::replaceAll(
incoming, " <3 ", "_loves_");
});
(See snippet source)
Registering a Custom Namer
Locally
If you want to use a specific namer for a specific test, the easiest way is via Options:
auto namer = ApprovalTests::TemplatedCustomNamer::create(
"{TestSourceDirectory}/{ApprovalsSubdirectory}/CustomName.{ApprovedOrReceived}.{FileExtension}");
ApprovalTests::Approvals::verify("Hello", ApprovalTests::Options().withNamer(namer));
(See snippet source)
Globally
If you ever want to create a custom namer, that’s used in multiple places, Approval Tests has a mechanism to change which namer it uses by default. Please note that you need to create a function that creates new namers.
auto default_namer_disposer = ApprovalTests::Approvals::useAsDefaultNamer(
[]() { return std::make_shared<FakeNamer>(); });
(See snippet source)
Hint: Many namer classes have a useAsDefaultNamer()
convenience
method to do this for you.
Alternative Namers
TemplatedCustomNamer
The easiest way to create a custom namer is to use a
TemplatedCustomNamer
.
As well as giving great flexibility, this introduces the ability to run Approval Tests on machines that do not have the source code, such as when doing cross-compilation
Here is an example:
ApprovalTests::TemplatedCustomNamer namer(
"/my/source/directory/{ApprovedOrReceived}/"
"{TestFileName}.{TestCaseName}.{FileExtension}");
(See snippet source)
Note: The character /
will be converted to \
on Windows
machines, at run-time.
Supported tags
auto testSourceDirectory = "{TestSourceDirectory}";
auto relativeTestSourceDirectory = "{RelativeTestSourceDirectory}";
auto approvalsSubdirectory = "{ApprovalsSubdirectory}";
auto testFileName = "{TestFileName}";
auto testCaseName = "{TestCaseName}";
auto approvedOrReceived = "{ApprovedOrReceived}";
auto fileExtension = "{FileExtension}";
(See snippet source)
Here is some output showing examples with these tags expanded:
For template: {RelativeTestSourceDirectory}/{ApprovalsSubdirectory}/{TestFileName}.{TestCaseName}.{ApprovedOrReceived}.{FileExtension}
Result: namers/approval_tests/TemplatedCustomNamerTests.Demo_all_namer_templates.approved.txt
With breakdown:
RelativeTestSourceDirectory = namers/
ApprovalsSubdirectory = approval_tests/
TestFileName = TemplatedCustomNamerTests
TestCaseName = Demo_all_namer_templates
ApprovedOrReceived = approved
FileExtension = txt
Also available:
{TestSourceDirectory} = <full path to sources>/ApprovalTests.cpp/tests/DocTest_Tests/namers/
(See snippet source)
Examples
If you would like to see an example of this running for scenarios where the execution is in a separate environment from the compilation, check out our out_of_source example.
SeparateApprovedAndReceivedDirectoriesNamer
The pattern used by this class for file names is:
auto path = "{TestSourceDirectory}/{ApprovalsSubdirectory}/{ApprovedOrReceived}/{TestFileName}.{TestCaseName}.{FileExtension}";
(See snippet source)
Which results in these file names:
./approved/{TestFileName}.{TestCaseName}.{FileExtension}
./received/{TestFileName}.{TestCaseName}.{FileExtension}
This layout enables you to use Beyond Compare 4 (or any other directory
comparison tool) to do a folder/directory comparison, in order to
compare pairs of files in the approved/
and received/
directories, and approve one or more files by copying them (without
renaming) from received/
to approved/
.
The approved/
and received/
directories are created
automatically.
To register this as your default namer, use:
auto default_namer_disposer =
ApprovalTests::SeparateApprovedAndReceivedDirectoriesNamer::useAsDefaultNamer();
(See snippet source)
When using this namer, you will want to add the following line to your
.gitignore
file:
**/received/