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\layout Title

Proposed Test Suite Design
\layout Author

Michael Hope (michaelh@juju.net.nz)
\layout Date


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\layout Abstract

This article describes the goals, requirements, and suggested specification
 for a test suite for the output of the Small Device C Compiler (sdcc).
 Also included is a short list of existing works.
 
\layout Section

Goals
\layout Standard

The main goals of a test suite for sdcc are 
\layout Enumerate

To allow developers to run regression tests to check that core changes do
 not break any of the many ports.
 
\layout Enumerate

To verify the core.
 
\layout Enumerate

To allow developers to verify individual ports.
 
\layout Enumerate

To allow developers to test port changes.
 
\layout Standard

This design only covers the generated code.
 It does not cover a test/unit test framework for the sdcc application itself,
 which may be useful.
\layout Standard

One side effect of (1) is that it requires that the individual ports pass
 the tests originally.
 This may be too hard.
 See the section on Exceptions below.
\layout Section

Requirements
\layout Subsection

Coverage
\layout Standard

The suite is intended to cover language features only.
 Hardware specific libraries are explicitly not covered.
\layout Subsection

Permutations
\layout Standard

The ports often generate different code for handling different types (Byte,
 Word, DWord, and the signed forms).
 Meta information could be used to permute the different test cases across
 the different types.
\layout Subsection

Exceptions
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The different ports are all at different levels of development.
 Test cases must be able to be disabled on a per port basis.
 Permutations also must be able to be disabled on a port level for unsupported
 cases.
 Disabling, as opposed to enabling, on a per port basis seems more maintainable.
\layout Subsection

Running
\layout Standard

The tests must be able to run unaided.
 The test suite must run on all platforms that sdcc runs on.
 A good minimum may be a subset of Unix command set and common tools, provided
 by default on a Unix host and provided through cygwin on a Windows host.
\layout Standard

The tests suits should be able to be sub-divided, so that the failing or
 interesting tests may be run separately.
\layout Subsection

Artifcats
\layout Standard

The test code within the test cases should not generate artifacts.
 An artifact occurs when the test code itself interferes with the test and
 generates an erroneous result.
\layout Subsection

Emulators
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sdcc is a cross compiling compiler.
 As such, an emulator is needed for each port to run the tests.
\layout Section

Existing works
\layout Subsection

DejaGnu
\layout Standard

DejaGnu is a toolkit written in Expect designed to test an interactive program.
 It provides a way of specifying an interface to the program, and given
 that interface a way of stimulating the program and interpreting the results.
 It was originally written by Cygnus Solutions for running against development
 boards.
 I believe the gcc test suite is written against DejaGnu, perhaps partly
 to test the Cygnus ports of gcc on target systems.
\layout Subsection

gcc test suite
\layout Standard

I don't know much about the gcc test suite.
 It was recently removed from the gcc distribution due to issues with copyright
 ownership.
 The code I saw from older distributions seemed more concerned with esoteric
 features of the language.
\layout Subsection

xUnit
\layout Standard

The xUnit family, in particular JUnit, is a library of in test assertions,
 test wrappers, and test suite wrappers designed mainly for unit testing.
 PENDING: More.
\layout Subsection

CoreLinux++ Assertion framework
\layout Standard

While not a test suite system, the assertion framework is an interesting
 model for the types of assertions that could be used.
 They include pre-condition, post-condition, invariants, conditional assertions,
 unconditional assertions, and methods for checking conditions.
\layout Section

Specification
\layout Standard

This specification borrows from the JUnit style of unit testing and the
 CoreLinux++ style of assertions.
 The emphasis is on maintainability and ease of writing the test cases.
\layout Subsection

Terms
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PENDING: Align these terms with the rest of the world.
\layout Itemize

An 
\emph on 
assertion
\emph default 
 is a statement of how things should be.
 PENDING: Better description, an example.
 
\layout Itemize

A 
\emph on 
test point
\emph default 
 is the smallest unit of a test suite, and consists of a single assertion
 that passes if the test passes.
 
\layout Itemize

A 
\emph on 
test case
\emph default 
 is a set of test points that test a certain feature.
 
\layout Itemize

A 
\emph on 
test suite
\emph default 
 is a set of test cases that test a certain set of features.
 
\layout Subsection

Test cases
\layout Standard

Test cases shall be contained in their own C file, along with the meta data
 on the test.
 Test cases shall be contained within functions whose names start with 'test'
 and which are descriptive of the test case.
 Any function that starts with 'test' will be automatically run in the test
 suite.
\layout Standard

To make the automatic code generation easier, the C code shall have this
 format 
\layout Itemize

Test functions shall start with 'test' to allow automatic detection.
 
\layout Itemize

Test functions shall follow the K&R intention style for ease of detection.
 i.e.
 the function name shall start in the left column on a new line below the
 return specification.
 
\layout Subsection

Assertions
\layout Standard

All assertions shall log the line number, function name, and test case file
 when they fail.
 Most assertions can have a more descriptive message attached to them.
 Assertions will be implemented through macros to get at the line information.
 This may cause trouble with artifacts.
\layout Standard

The following definitions use C++ style default arguments where optional
 messages may be inserted.
 All assertions use double opening and closing brackets in the macros to
 allow them to be compiled out without any side effects.
 While this is not required for a test suite, they are there in case any
 of this code is incorporated into the main product.
\layout Standard

Borrowing from JUnit, the assertions shall include 
\layout Itemize

FAIL((String msg = 
\begin_inset Quotes eld
\end_inset 

Failed
\begin_inset Quotes erd
\end_inset 

)).
 Used when execution should not get here.
 
\layout Itemize

ASSERT((Boolean cond, String msg = 
\begin_inset Quotes eld
\end_inset 

Assertion failed
\begin_inset Quotes erd
\end_inset 

).
 Fails if cond is false.
 Parent to REQUIRE and ENSURE.
 
\layout Standard

JUnit also includes may sub-cases of ASSERT, such as assertNotNull, assertEquals
, and assertSame.
\layout Standard

CoreLinux++ includes the extra assertions 
\layout Itemize

REQUIRE((Boolean cond, String msg = 
\begin_inset Quotes eld
\end_inset 

Precondition failed
\begin_inset Quotes erd
\end_inset 

).
 Checks preconditions.
 
\layout Itemize

ENSURE((Boolean cond, String msg = 
\begin_inset Quotes eld
\end_inset 

Postcondition failed
\begin_inset Quotes erd
\end_inset 

).
 Checks post conditions.
 
\layout Itemize

CHECK((Boolean cond, String msg = 
\begin_inset Quotes eld
\end_inset 

Check failed
\begin_inset Quotes erd
\end_inset 

)).
 Used to call a function and to check that the return value is as expected.
 i.e.
 CHECK((fread(in, buf, 10) != -1)).
 Very similar to ASSERT, but the function still gets called in a release
 build.
 
\layout Itemize

FORALL and EXISTS.
 Used to check conditions within part of the code.
 For example, can be used to check that a list is still sorted inside each
 loop of a sort routine.
 
\layout Standard

All of FAIL, ASSERT, REQUIRE, ENSURE, and CHECK shall be available.
\layout Subsection

Meta data
\layout Standard

PENDING: It's not really meta data.
\layout Standard

Meta data includes permutation information, exception information, and permutati
on exceptions.
\layout Standard

Meta data shall be global to the file.
 Meta data names consist of the lower case alphanumerics.
 Test case specific meta data (fields) shall be stored in a comment block
 at the start of the file.
 This is only due to style.
\layout Standard

A field definition shall consist of 
\layout Itemize

The field name 
\layout Itemize

A colon.
 
\layout Itemize

A comma separated list of values.
 
\layout Standard

The values shall be stripped of leading and trailing white space.
\layout Standard

Permutation exceptions are by port only.
 Exceptions to a field are specified by a modified field definition.
 An exception definition consists of
\layout Itemize

The field name.
 
\layout Itemize

An opening square bracket.
 
\layout Itemize

A comma separated list of ports the exception applies for.
 
\layout Itemize

A closing square bracket.
 
\layout Itemize

A colon.
 
\layout Itemize

The values to use for this field for these ports.
 
\layout Standard

An instance of the test case shall be generated for each permutation of
 the test case specific meta data fields.
\layout Standard

The runtime meta fields are 
\layout Itemize

port - The port this test is running on.
 
\layout Itemize

testcase - The name of this test case.
 
\layout Itemize

function - The name of the current function.
 
\layout Standard

Most of the runtime fields are not very usable.
 They are there for completeness.
\layout Standard

Meta fields may be accessed inside the test case by enclosing them in curly
 brackets.
 The curly brackets will be interpreted anywhere inside the test case, including
 inside quoted strings.
 Field names that are not recognised will be passed through including the
 brackets.
 Note that it is therefore impossible to use some strings within the test
 case.
\layout Standard

Test case function names should include the permuted fields in the name
 to reduce name collisions.
\layout Subsection

An example
\layout Standard

I don't know how to do pre-formatted text in LaTeX.
 Sigh.
\layout Standard

The following code generates a simple increment test for all combinations
 of the storage classes and all combinations of the data sizes.
 This is a bad example as the optimiser will often remove most of this code.
\layout Standard


\family typewriter 
/** Test for increment.
 
\layout Standard


\family typewriter 
type: char, int, long
\layout Standard


\family typewriter 
Z80 port does not fully support longs (4 byte)
\layout Standard


\family typewriter 
type[z80]: char, int
\layout Standard


\family typewriter 
class: 
\begin_inset Quotes eld
\end_inset 


\begin_inset Quotes erd
\end_inset 

, register, static */
\layout Standard


\family typewriter 
static void
\layout Standard


\family typewriter 
testInc{class}{types}(void)
\layout Standard


\family typewriter 
{
\layout Standard


\family typewriter 
{class} {type} i = 0; 
\layout Standard


\family typewriter 
i = i + 1;
\layout Standard


\family typewriter 
ASSERT((i == 1));
\layout Standard


\family typewriter 
}
\the_end