Add test suite framework summary

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Azim Khan 2018-07-02 16:01:04 +01:00 committed by Mohammad Azim Khan
parent 63ab501aa7
commit aee05bbe70

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@ -19,18 +19,147 @@
# This file is part of mbed TLS (https://tls.mbed.org)
"""
This script dynamically generates test suite code for Mbed TLS, by
taking following input files.
This script is a key part of Mbed TLS test suites framework. For
understanding the script it is important to understand the
framework. This doc string contains a summary of the framework
and explains the function of this script.
Mbed TLS test suites:
=====================
Scope:
------
The test suites focus on unit testing the crypto primitives and also
include x509 parser tests. Tests can be added to test any MBED TLS
module. However, the framework is not capable of testing SSL
protocol, since that requires full stack execution and that is best
tested as part of the system test.
Test case definition:
---------------------
Tests are defined in a test_suite_<module>[.<optional sub module>].data
file. A test definition contains:
test name
optional build macro dependencies
test function
test parameters
Test dependencies are build macros that can be specified to indicate
the build config in which the test is valid. For example if a test
depends on a feature that is only enabled by defining a macro. Then
that macro should be specified as a dependency of the test.
Test function is the function that implements the test steps. This
function is specified for different tests that perform same steps
with different parameters.
Test parameters are specified in string form separated by ':'.
Parameters can be of type string, binary data specified as hex
string and integer constants specified as integer, macro or
as an expression. Following is an example test definition:
X509 CRL Unsupported critical extension (issuingDistributionPoint)
depends_on:MBEDTLS_PEM_PARSE_C:MBEDTLS_RSA_C:MBEDTLS_SHA256_C
mbedtls_x509_crl_parse:"data_files/crl-idp.pem":MBEDTLS_ERR_X509_INVALID_EXTENSIONS + MBEDTLS_ERR_ASN1_UNEXPECTED_TAG
Test functions:
---------------
Test functions are coded in C in test_suite_<module>.function files.
Functions file is itself not compilable and contains special
format patterns to specify test suite dependencies, start and end
of functions and function dependencies. Check any existing functions
file for example.
Execution:
----------
Tests are executed in 3 steps:
- Generating test_suite_<module>[.<optional sub module>].c file
for each corresponding .data file.
- Building each source file into executables.
- Running each executable and printing report.
Generating C test source requires more than just the test functions.
Following extras are required:
- Process main()
- Reading .data file and dispatching test cases.
- Platform specific test case execution
- Dependency checking
- Integer expression evaluation
- Test function dispatch
Build dependencies and integer expressions (in the test parameters)
are specified as strings in the .data file. Their run time value is
not known at the generation stage. Hence, they need to be translated
into run time evaluations. This script generates the run time checks
for dependencies and integer expressions.
Similarly, function names have to be translated into function calls.
This script also generates code for function dispatch.
The extra code mentioned here is either generated by this script
or it comes from the input files: helpers file, platform file and
the template file.
Helper file:
------------
Helpers file contains common helper/utility functions and data.
Platform file:
--------------
Platform file contains platform specific setup code and test case
dispatch code. For example, host_test.function reads test data
file from host's file system and dispatches tests.
In case of on-target target_test.function tests are not dispatched
on target. Target code is kept minimum and only test functions are
dispatched. Test case dispatch is done on the host using tools like
Greentea.
Template file:
---------
Template file for example main_test.function is a template C file in
which generated code and code from input files is substituted to
generate a compilable C file. It also contains skeleton functions for
dependency checks, expression evaluation and function dispatch. These
functions are populated with checks and return codes by this script.
Template file contains "replacement" fields that are formatted
strings processed by Python str.format() method.
This script:
============
Core function of this script is to fill the template file with
code that is generated or read from helpers and platform files.
This script replaces following fields in the template and generates
the test source file:
{test_common_helpers} <-- All common code from helpers.function
is substituted here.
{functions_code} <-- Test functions are substituted here
from the input test_suit_xyz.function
file. C preprocessor checks are generated
for the build dependencies specified
in the input file. This script also
generates wrappers for the test
functions with code to expand the
string parameters read from the data
file.
{expression_code} <-- This script enumerates the
expressions in the .data file and
generates code to handle enumerated
expression Ids and return the values.
{dep_check_code} <-- This script enumerates all
build dependencies and generate
code to handle enumerated build
dependency Id and return status: if
the dependency is defined or not.
{dispatch_code} <-- This script enumerates the functions
specified in the input test data file
and generates the initializer for the
function table in the template
file.
{platform_code} <-- Platform specific setup and test
dispatch code.
test_suite_xyz.function - Test suite functions file contains test
functions.
test_suite_xyz.data - Contains test case vectors.
main_test.function - Template to substitute generated test
functions, dispatch code, dependency
checking code etc.
platform .function - Platform specific initialization and
platform code.
helpers.function - Common/reusable data and functions.
"""