Mbed TLS test framework

This document is an overview of the Mbed TLS test framework and test tools.

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Unit tests

See https://mbed-tls.readthedocs.io/en/latest/kb/development/test_suites

Unit test descriptions

Each test case has a description which succinctly describes for a human audience what the test does. The first non-comment line of each paragraph in a .data file is the test description. The following rules and guidelines apply:

  • Test descriptions may not contain semicolons, line breaks and other control characters, or non-ASCII characters.
    Rationale: keep the tools that process test descriptions (generate_test_code.py, outcome file tools) simple.
  • Test descriptions must be unique within a .data file. If you can't think of a better description, the convention is to append #1, #2, etc.
    Rationale: make it easy to relate a failure log to the test data. Avoid confusion between cases in the outcome file.
  • Test descriptions should be a maximum of 66 characters.
    Rationale: 66 characters is what our various tools assume (leaving room for 14 more characters on an 80-column line). Longer descriptions may be truncated or may break a visual alignment.
    We have a lot of test cases with longer descriptions, but they should be avoided. At least please make sure that the first 66 characters describe the test uniquely.
  • Make the description descriptive. “foo: x=2, y=4” is more descriptive than “foo #2”. “foo: 0<x<y, both even” is even better if these inequalities and parities are why this particular test data was chosen.
  • Avoid changing the description of an existing test case without a good reason. This breaks the tracking of failures across CI runs, since this tracking is based on the descriptions.

tests/scripts/check_test_cases.py enforces some rules and warns if some guidelines are violated.

TLS tests

SSL extension tests

SSL test case descriptions

Each test case in ssl-opt.sh has a description which succinctly describes for a human audience what the test does. The test description is the first parameter to run_test.

The same rules and guidelines apply as for unit test descriptions. In addition, the description must be written on the same line as run_test, in double quotes, for the sake of check_test_cases.py.

SSL cipher suite tests

Each test case in compat.sh has a description which succinctly describes for a human audience what the test does. The test description is $TITLE defined in run_client.

The same rules and guidelines apply as for unit test descriptions. In addition, failure cause in compat.sh is not classified as ssl-opt.sh, so the information of failed log files are followed as prompt.

Running tests

Outcome file

Generating an outcome file

Unit tests, ssl-opt.sh and compat.sh record the outcome of each test case in a test outcome file. This feature is enabled if the environment variable MBEDTLS_TEST_OUTCOME_FILE is set. Set it to the path of the desired file.

If you run all.sh --outcome-file test-outcome.csv, this collects the outcome of all the test cases in test-outcome.csv.

Outcome file format

The outcome file is in a CSV format using ; (semicolon) as the delimiter and no quoting. This means that fields may not contain newlines or semicolons. There is no title line.

The outcome file has 6 fields:

  • Platform: a description of the platform, e.g. Linux-x86_64 or Linux-x86_64-gcc7-msan.
  • Configuration: a unique description of the configuration (config.h).
  • Test suite: test_suite_xxx, ssl-opt or compat.
  • Test case: the description of the test case.
  • Result: one of PASS, SKIP or FAIL.
  • Cause: more information explaining the result.