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Overview</a></div> +<div class="fancy-toc2"><a href="#history">1.1. History</a></div> +<div class="fancy-toc1"><a href="#operation">2. Operation</a></div> +<div class="fancy-toc1"><a href="#generating_a_test_program">3. Generating A Test Program</a></div> +<div class="fancy-toc2"><a href="#test_automation_scripts">3.1. Test Automation Scripts</a></div> +<div class="fancy-toc1"><a href="#test_coverage">4. Test Coverage</a></div> +<div class="fancy-toc1"><a href="#mutation_testing">5. Mutation Testing</a></div> +<div class="fancy-toc1"><a href="#th3_license">6. TH3 License</a></div> +</div> +</div> +<script> +function toggle_toc(){ +var sub = document.getElementById("toc_sub") +var mk = document.getElementById("toc_mk") +if( sub.style.display!="block" ){ +sub.style.display = "block"; +mk.innerHTML = "▼"; +} else { +sub.style.display = "none"; +mk.innerHTML = "►"; +} +} +</script> +</div> + + + + +<h1 id="overview"><span>1. </span>Overview</h1> + +<p>SQLite Test Harness #3 (hereafter "TH3") is one of +<a href="testing.html#harnesses">three test harnesses</a> used for testing SQLite. +TH3 meets the following objectives:</p> + +<ul> +<li><p> TH3 is able to run on embedded platforms that lack the support + infrastructure of workstations.</p></li> + +<li><p> TH3 tests SQLite in an as-deployed configuration using only + published and documented interfaces. + In other words, TH3 tests the compiled object code, not + the source code, thus verifying that no problems were introduced + by compiler bugs. "Test what you fly and fly what you test."</p></li> + +<li><p> TH3 checks SQLite's response to out-of-memory errors, disk I/O + errors, and power loss during transaction commit. </p></li> + +<li><p> TH3 exercises SQLite in a variety of run-time configurations + (UTF8 vs UTF16, different pages sizes, varying journal modes, etc.) + </p></li> + +<li><p> TH3 achieves 100% branch test coverage (and 100% + <a href="https://en.wikipedia.org/wiki/Modified_condition/decision_coverage">MC/DC</a>) + over the SQLite core. + (Test coverage of extensions such as FTS and RTREE is less than 100%). + </p></li> +</ul> + +<p>TH3 was originally written for validation testing only, but has +subsequently been used for development testing and debugging +as well, and has proven very helpful in those roles. A full-coverage +test takes less than five minutes on a workstation and hence +serves as a fast regression test during day-to-day maintenance +of the SQLite code base.</p> + +<h2 id="history"><span>1.1. </span>History</h2> + +<p>TH3 originated from an effort to test SQLite on +<a href="https://en.wikipedia.org/wiki/Symbian">SymbianOS</a>. +Prior to TH3, all SQLite tests were run using the +<a href="http://www.tcl.tk/">TCL</a> script language, but TCL would not (easily) +compile on SymbianOS which made testing difficult. The first attempt +to remedy this problem was the "TH1" (Test Harness #1) scripting +language - a reimplementation of parts of the TCL language in a +more portable form that would compile and run on SymbianOS, and +that was sufficient to run the SQLite tests. TH1 +did not survive as a standard testing tool for SQLite, +but it did find continued service as a +scripting language used to customize the +<a href="http://www.fossil-scm.org/">Fossil</a> version control system. +There was also a "Test Harness #2" which was an attempt to +create a simple scripting language using operator prefix notation +to drive tests. TH3 was the third attempt. + +</p><p>At about that same time, some avionics manufacturers were +expressing interest in SQLite, which prompted the SQLite developers +to design TH3 to support the rigorous testing standards of +<a href="https://en.wikipedia.org/wiki/DO-178B">DO-178B</a>. + +</p><p>The first code for TH3 was laid down on 2008-09-25. +An intense effort over the next 10 months resulted in TH3 achieving +100% MC/DC on 2009-07-25. The TH3 code continues to be improved and +expanded. + +</p><p>As of 2018-05-19, the TH3 source tree consists +and well over 500,000 lines of source code in 1709 separate files. + +</p><h1 id="operation"><span>2. </span>Operation</h1> + +<p>TH3 is a test program generator. The output of TH3 is a program +implemented in C-code and intended to be +linked against the SQLite library under test. The generated test +program is compiled and run on the target platform in order to verify +correct operation of SQLite on that platform.</p> + +<p>The inputs to TH3 are test modules written in C or SQL and +small configuration +files that determine how to initialize SQLite. The +TH3 package includes 1,444 test +modules and more than 47 configurations (as of 2018-05-19). +New modules and configurations +can be added to customize TH3 for specialized applications. +Each time TH3 is run, it reads +a subset of the available test modules and configuration files to generate +a custom C program that performs all of the specified tests under all +specified configurations. A complete test of SQLite normally involves running +TH3 multiple times to generate multiple test programs covering different +aspects of SQLite's operation, then linking all test programs against +a common SQLite library and running them separately on the target platform. +</p> + +<p>There are no arbitrary limits in TH3. One could generate a +single test program that contained all test modules and all configuration files. +However, such a test program might be too large to deploy on embedded +platforms. (As of 2018-05-19, a full-up TH3 test is over 850,000 lines and +58MB of C code.) TH3 provides the ability to break the library of test +modules up into smaller, more easily digested pieces.</p> + +<p>Each individual test module might contain dozens, hundreds, or thousands +of separate tests. The test modules can be written in C or as scripts of +SQL or a mixture of the two. About two-thirds of the existing test modules are +written in pure SQL with the remainder either in pure C or a combination +of C and SQL. +</p> + +<p>Each test module file contains a header which describes the circumstances +under which the test is valid. For a particular configuration, only those +modules that are compatible with the configuration are run. </p> + +<h1 id="generating_a_test_program"><span>3. </span>Generating A Test Program</h1> + +<p>The TH3 program generator is a TCL script named "<tt>mkth3.tcl</tt>". +To generate a test program, one has merely to run this script and supply +the names of files containing test modules and configurations on the +command line. Test modules are files that use the "<tt>.test</tt>" suffix +and configurations are files that use the "<tt>.cfg</tt>" suffix. A +typical invocation of mkth3.tcl might look something like the following:</p> + +<div class="codeblock"><pre>tclsh mkth3.tcl *.test *.cfg >testprog1.c +</pre></div> + +<p>The output from the mkth3.tcl script is a C program that contains +everything needed to run the tests - everything that is except for +the SQLite library itself. The generated test program contains +implementations for all of the support interfaces used by the test +modules and it contains the <tt>main()</tt> routine that drives the +tests. To convert the test program into a working executable, simply +compile it against SQLite:</p> + +<div class="codeblock"><pre>cc -o testprog1 testprog1.c sqlite3.c +</pre></div> + +<p>The compilation step shown immediately above is merely representative. +In a working installation, one would normally want +to specify optimization parameters and compile-time switches on the +compiler command line.</p> + +<p>For testing on embedded systems, the mkth3.tcl script and the compiler +steps shown above are performed on an ordinary workstation using +a cross-compiler, then the resulting test program is +transferred onto the device to be run.</p> + +<p>Once the test program is generated, it is run with no arguments to +perform the tests. Progress information as well as error diagnostics +appear on standard output. (Alternative output arrangements can be made +using a compile-time option for embedded devices that lack a standard +output channel.) The program returns zero if there are no +errors and non-zero if any problems were detected.</p> + +<p>Typical output from a single TH3 test program run looks like this: + +</p><div class="codeblock"><pre>With SQLite 3.8.11 2015-05-15 04:13:15 56ef98a04765c34c1c2f3ed7a6f03a732f3b886e +-DSQLITE_COVERAGE_TEST +-DSQLITE_NO_SYNC +-DSQLITE_SYSTEM_MALLOC +-DSQLITE_THREADSAFE=1 +Config-begin c1. +Begin c1.pager08 +End c1.pager08 +Begin c1.build33 +End c1.build33 +Begin c1.orderby01 +End c1.orderby01 +<i>... 15014 lines of output omitted ....</i> +Begin 64k.syscall01 +End 64k.syscall01 +Begin 64k.build01 +End 64k.build01 +Begin 64k.auth01 +End 64k.auth01 +Config-end 64k. TH3 memory used: 6373738 +Config-begin wal1. +Begin wal1.wal37 +End wal1.wal37 +Config-end wal1. TH3 memory used: 100961 +All 226 VDBE coverage points reached +th3: 0 errors out of 1442264 tests in 213.741 seconds. 64-bit little-endian +th3: SQLite 3.8.11 2015-05-15 04:13:15 56ef98a04765c34c1c2f3ed7a6f03a732f3b886e +</pre></div> + +<p>The output begins with a report of the <a href="c3ref/c_source_id.html">SQLITE_SOURCE_ID</a> +(cross-checked again <a href="c3ref/libversion.html">sqlite3_sourceid()</a>) for the +SQLite under test and the compile-time options used as reported +by <a href="c3ref/compileoption_get.html">sqlite3_compileoption_get()</a>. The output concludes with a summary +of the test results and a repeat of the <a href="c3ref/c_source_id.html">SQLITE_SOURCE_ID</a>. If any +errors are detected, additional lines detail the problem. The error +reporting lines always begin with a single space character so that they +can be quickly extracted from large output files using: + +</p><div class="codeblock"><pre>grep "^ " +</pre></div> + +<p>The default output shows the beginning and end of each configuration +and test module combination. In the example above "c1" and "64k" are +configurations and "pager08", "build33", "orderby01", etc. are test modules. +Compile-time and run-time options are available to increase or decrease +the amount of output. +The output can be increased by showing each test case within each +test module. The output can be decreased +by degrees: omitting test modules starts and stops, +omitting configuration starts and stops, and finally by omitting all output. + +</p><h2 id="test_automation_scripts"><span>3.1. </span>Test Automation Scripts</h2> + +<p>TH3 comes with additional TCL scripts that help automate the testing +process on workstations. The "th3make" script automatically runs "mkth3.tcl" +and "gcc" and then runs the resulting test program and checks the results. +Arguments to th3make include all of the "*.test" test modules and +"*.cfg" configurations that are to be included in the test. Additional +options to th3make can cause the test program to be compiled using different +compilers (GCC, Clang, MSVC), to use different output verbosity levels, to +run the test program under valgrind, to check the output for coverage using +gcov, and so forth. The th3make script also accepts "*.rc" filenames as +arguments. These *.rc files are just collections of other arguments that +are commonly used together for a single purpose. For example, the "quick.rc" +file contains a set of eight arguments to th3make that run a fast (3-minute) +full-coverage test. This allows the operator to type "./th3make quick.rc" as +a short-cut to typing out all of the required command-line options. The +following are a few of the more than 40 available *.rc files: + +</p><ul> +<li><b>alignment</b><i>N</i><b>.rc</b> - + These files contain -D options to the compiler that are used by + various notable downstreams. +</li><li><b>cov.rc</b> - Options for measuring test coverage +</li><li><b>extensions.rc</b> - Options to enable <a href="fts3.html#fts4">FTS4</a>, <a href="rtree.html">R-Trees</a>, + and <a href="fileformat2.html#stat4tab">STAT4</a>. +</li><li><b>fast.rc</b> - Run most tests, including those not needed for + coverage, skipping only soak tests, using delivery compiler options + (ex: -O3) +</li><li><b>memdebug.rc</b> - like test.rc but also enable + <a href="compile.html#memdebug">-DSQLITE_MEMDEBUG</a>. +</li><li><b>min.rc</b> - Run the minimum set of tests needed for 100% coverage. +</li><li><b>quick.rc</b> - Run all tests required for 100% coverage tests + using -Os and <a href="compile.html#debug">-DSQLITE_DEBUG</a>. +</li><li><b>test.rc</b> - Run the same tests as in fast.rc but without + compiler optimization and enabling options like + <a href="compile.html#debug">-DSQLITE_DEBUG</a> and + -DSQLITE_ENABLE_EXPENSIVE_ASSERT. +</li><li><b>test-ex.rc</b> - long-running soak tests. +</li></ul> + +<p>The TH3 repository also includes the "multitest.tcl" script, another +TCL script used to automate TH3 testing on workstations. Multitest.tcl +automatically compiles SQLite, then +runs ./th3make repeatedly with a variety of alignments, and captures +the output in a succinct summary screen. A typical multitest.tcl run +generates output that looks like this: + +</p><div class="codeblock"><pre>./multitest.tcl -q --jobs 3 +start-time: 2018-05-19 03:17:12 UTC +file mkdir sqlite3bld +cd sqlite3bld +exec sh /ramdisk/sqlite/configure +file copy -force config.h ../config.h +exec make clean sqlite3.c +file rename sqlite3.c ../sqlite3.c +file rename sqlite3.h ../sqlite3.h +exec make clean sqlite3.c OPTS=-DSQLITE_ENABLE_UPDATE_DELETE_LIMIT=1 +file rename sqlite3.c ../sqlite3udl.c +exec make clean sqlite3.c OPTS=-DSQLITE_SMALL_STACK=1 +file rename sqlite3.c ../sqlite3ss.c +cd .. +******************************************************************************* +t01: cov.rc.................................................... Ok (00:03:42) +t02: cov.rc ++STAT4 ++DESERIALIZE -D_HAVE_SQLITE_CONFIG_H...... Ok (00:04:45) +t03: vfs-cov.rc................................................ Ok (00:03:59) +t04: demo.rc................................................... Ok (00:00:05) +t07: test.rc ../th3private/*.test.............................. Ok (00:00:21) +t08: test.rc ../th3private/*.test ++STAT4...................... Ok (00:01:41) +t05: quick.rc.................................................. Ok (00:04:26) +t09: quick.rc ~TEST_REALLOC_STRESS -funsigned-char............. Ok (00:05:39) +t10: quick.rc ~THREADSAFE=0 -DLONGDOUBLE_TYPE=double........... Ok (00:03:24) +t06: quick.rc extensions.rc -D_HAVE_SQLITE_CONFIG_H............ Ok (00:09:03) +t11: quick.rc sqlite3ss.c ~MAX_ATTACHED=125.................... Ok (00:04:39) +t12: quick.rc ~BYTEORDER=0 ++RTREE............................. Ok (00:07:28) +t13: quick.rc ~DISABLE_INTRINSIC ++RTREE....................... Ok (00:07:31) +t16: quick.rc ~TRACE_SIZE_LIMIT=15 cov1/main16.test............ Ok (00:00:22) +t14: quick.rc ~DIRECT_OVERFLOW_READ -fsigned-char.............. Ok (00:04:35) +t15: quick.rc ~UNTESTABLE ~EXTRA_IFNULLROW..................... Ok (00:01:44) +t17: quick.rc ~MAX_MMAP_SIZE=0................................. Ok (00:04:46) +t18: quick.rc ++NULL_TRIM ++OFFSET_SQL_FUNC.................... Ok (00:04:47) +t19: quick.rc ++BATCH_ATOMIC_WRITE ++DESERIALIZE............... Ok (00:05:41) +t20: lean1.rc quick.rc......................................... Ok (00:03:09) +t22: test.rc alignment2.rc sqlite3udl.c........................ Ok (00:44:22) +t21: test.rc alignment1.rc..................................... Ok (01:02:32) +t23: memdebug1.rc extensions.rc................................ Ok (01:49:58) +t25: valgrind1.rc -O3 extensions.rc............................ Ok (00:56:08) +t24: memdebug2.rc extensions.rc................................ Ok (01:43:34) +t27: test-ex1.rc............................................... Ok (00:45:00) +t26: valgrind2.rc -O3 extensions.rc............................ Ok (01:02:52) +t29: test-ex3.rc............................................... Ok (00:31:48) +t28: test-ex2.rc............................................... Ok (01:12:03) +t30: test-ex4.rc............................................... Ok (01:09:47) +t32: test.rc alignment4.rc -m32 CC=clang....................... Ok (00:48:31) +t31: test.rc alignment3.rc sqlite3udl.c........................ Ok (01:22:29) +t34: test.rc alignment6.rc..................................... Ok (00:35:31) +t33: test.rc alignment5.rc extensions.rc....................... Ok (00:59:33) +t35: test.rc alignment7.rc..................................... Ok (00:44:10) +t40: fast.rc alignment2.rc sqlite3udl.c........................ Ok (00:15:46) +t39: fast.rc alignment1.rc extensions.rc -m32.................. Ok (00:33:19) +t36: test.rc ~MUTATION_TEST.................................... Ok (00:35:45) +t42: fast.rc alignment4.rc..................................... Ok (00:13:03) +t43: fast.rc alignment5.rc..................................... Ok (00:13:32) +t44: fast.rc alignment6.rc..................................... Ok (00:11:41) +t41: fast.rc alignment3.rc sqlite3udl.c........................ Ok (00:26:31) +t45: fast.rc alignment7.rc..................................... Ok (00:12:57) +t46: fast.rc -fsanitize=undefined.............................. Ok (00:38:18) +******************************************************************************* +0 failures on 44 th3makes and 198583082 tests in (07:16:01) 3 cores on bella +SQLite 3.24.0 2018-05-18 17:58:33 c6071ac99cfa4b6272ac4d739fc61a85acb544f6c1c2a +</pre></div> + +<p>As can be seen above, a single run +of multitest.tcl invokes th3make dozens of times and takes between 12 and 24 +CPU hours. The middle section of the output shows the arguments to each +individual th3make run and the result and elapse time for that th3make. +All build products and output for the separate th3make runs are +captures in subdirectories for post-test analysis. +The two-line summary at the bottom shows the total number of errors and tests +over all th3make runs and the total elapse time, together with the +<a href="c3ref/c_source_id.html">SQLITE_SOURCE_ID</a> information for the version of SQLite that was +tested. This summary information is recorded in the +<a href="https://www.sqlite.org/checklists">release +checklist</a> during final testing. + +</p><p>Abbreviations are applied in the multitest.tcl output so that +each th3make invocation will fit on a single 80-column output line. +The initial "th3make" verb is omitted. +"~" is shorthand for "-DSQLITE_" and "++" is stands for +"-DSQLITE_ENABLE". Hence, multitest.tcl output line + +</p><div class="codeblock"><pre>quick.rc ~DISABLE_INTRINSIC ++RTREE +</pre></div> + +<p>Really means + +</p><div class="codeblock"><pre>th3make quick.rc -DSQLITE_DISABLE_INTRINSIC -DSQLITE_ENABLE_RTREE +</pre></div> + +<h1 id="test_coverage"><span>4. </span>Test Coverage</h1> + +<p>Using one particular subset of the available TH3 test modules (the "cov1" +tests) SQLite obtained +<a href="testing.html#coverage">100% branch test coverage</a> and 100% <a href="testing.html#mcdc">MC/DC</a> as measured +by <a href="http://gcc.gnu.org/onlinedocs/gcc/Gcov.html">gcov</a> +on Linux x86 and x86_64 hardware. All releases of SQLite since +<a href="releaselog/3_6_17.html">version 3.6.17</a> (2009-08-10) have been tested to this standard. +The SQLite developers +are committed to maintaining 100% branch coverage and MC/DC for all +future releases of SQLite.</p> + +<p>The cov1 test set used to obtain 100% branch test coverage are only a +subset of the tests currently implemented using TH3. New test modules are +added on a regular basis.</p> + +<a name="muttest"></a> + +<h1 id="mutation_testing"><span>5. </span>Mutation Testing</h1> + +<p>The TH3 source tree contains a scripted name +"mutation-test.tcl" that automates the process of +<a href="testing.html#mutationtests">mutation testing</a>. + +</p><p>The mutation-test.tcl script takes care of all of the details for +running a mutation test: + +</p><ol> +<li> The script compiles the TH3 test harness into machine code ("th3.o") if + necessary. +</li><li> The script compiles the sqlite3.c source file into assembly language + ("sqlite3.s") if necessary. +</li><li> The script loops through instructions in the assembly language file + to locate branch operations. + <ol type="a"> + <li>The script makes a copy of the original sqlite3.s file. + </li><li>The copy is edited to change the branch instruction into either + a no-op or an unconditional jump. + </li><li>The copy of sqlite3.s is assembled into sqlite3.o then linked + again th3.o to generate the "th3" executable. + </li><li>The "th3" binary is run and the output checked for errors. + </li></ol> +</li><li> The script shows progress for each cycle of the previous step then + displays a summary of "survivors" at the end. A "survivor" is a + mutation that was not detected by TH3. +</li></ol> + +<p>Mutation testing can be slow, since each test can take up to 5 +minutes on a fast workstation, and there are two tests for each +branch instructions, and over 20,000 branch instructions. Efforts are +made to expedite operation. For example, TH3 is compiled in such a +way that it exits as soon as it finds the first error, and as many +of the mutations are easily detected, many cycles happen in only +a few seconds. Nevertheless, the mutation-test.tcl script includes +command-line options to limit the range of code lines tested so that +mutation testing only needs to be performed on blocks of code that +have recently changed. + +</p><h1 id="th3_license"><span>6. </span>TH3 License</h1> + +<p>SQLite itself is in the <a href="copyright.html">public domain</a> and +can be used for any purpose. But TH3 is proprietary and requires a license. +</p> + +<p>Even though open-source users do not have direct access to TH3, all +users of SQLite benefit from TH3 indirectly since each version of SQLite is +validated running TH3 on multiple platforms (Linux, Windows, WinRT, Mac, +OpenBSD) prior to release. So anyone using an official release +of SQLite can deploy their application with the confidence of knowing that +it has been tested using TH3. They simply cannot rerun those tests +themselves without purchasing a TH3 license.</p> +<p align="center"><small><i>This page last modified on <a href="https://sqlite.org/docsrc/honeypot" id="mtimelink" data-href="https://sqlite.org/docsrc/finfo/pages/th3.in?m=7955ba7a189628a83">2018-05-19 14:21:54</a> UTC </small></i></p> + |