[/
 / Copyright (c) 2003 Boost.Test contributors 
 /
 / Distributed under the Boost Software License, Version 1.0. (See accompanying
 / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 /]


[section:tools_assertion_severity_level Assertion severity level]

There are three *levels* of assertions and all the testing tools are supplied in these three flavours/levels. These levels 
have different meaning on the consistency of the test case:

* `REQUIRE` which implements a *requirements* : this is a strong condition for the operations following the assertion to be valid. 
  This type of assertions should be used when a pre-condition for running the test is not met or when the test-case cannot continue.
  If such as assertion fails, the test case execution stops immediately, and the test-case is flagged as /failed/.
* `CHECK` for standard *checks*: this is the most commonly used assertion level. If the statement evaluates to `false`, the test case is 
  flagged as failed but its execution continues. 
* `WARN` which stands for *warnings*: this is an assertion providing information. The test case execution continues and a warning message is logged. 
  The warning does not change the success status of a test case. This level of assertion can be used 
  to validate aspects less important then correctness: performance, portability, usability, etc.

For example: 

* [link boost_test.utf_reference.testing_tool_ref.assertion_boost_level_throw `BOOST_REQUIRE_THROW`], __BOOST_TEST_REQUIRE__ 
* `BOOST_CHECK_THROW`, `BOOST_TEST` [footnote __BOOST_TEST__ is equivalent to `BOOST_TEST_CHECK`]
* `BOOST_WARN_THROW`, `BOOST_TEST_WARN`

These three levels of assertions are filtered by the framework and reported into the test log and output: 

# If an assertion designated by the tool passes, confirmation message can be printed in log output 
  [footnote to manage what messages appear in the test log stream, set the proper [link boost_test.utf_reference.rt_param_reference.log_level `log_level`]].
# If an assertion designated by the tool fails, the following will happen, depending on the assertion level
  [footnote in some cases log message can be slightly different to reflect failed tool specifics, see [link boost_test.testing_tools.reports here]]:

[table:assertions_severity_levels Assertions severity levels
  [
    [Level]
    [Test log content]
    [Errors counter]
    [Test execution]
  ]
  
  [
    [WARN]
    [warning in `<test-case-name>`: condition `<assertion description>` is not satisfied]
    [not affected]
    [continues]
  ]
  [
    [CHECK]
    [error in `<test-case-name>`: test `<assertion description>` failed]
    [increased]
    [continues]
  ]
  [
    [REQUIRE]
    [fatal error in `<test-case-name>`: critical test `<assertion description>` failed]
    [increased]
    [aborts]
  ]
]

The granularity of the report depends on the current [link boost_test.utf_reference.rt_param_reference.log_level log level] and 
[link boost_test.utf_reference.rt_param_reference.report_level report level].

[note in the above table, the ['test execution] is related to the current test case ['only]. Hence ['"aborts"] means 
 that the current test case is aborted, but other test cases in the test tree are still executed.]
 
[endsect] [/ assertions severity level]
