21 роки тому · 4678f4e40b
--- a/tests/readme-writing-compiler-tests.html
+++ b/tests/readme-writing-compiler-tests.html
@@ -0,0 +1,432 @@
 <html>
 <!-- <![CDATA[ putDataHere ]]> -->
 <title>Writing tests for the AspectJ compiler
 </title>
 <body>
 <h2>Writing tests for the AspectJ compiler
 </h2>
 The AspectJ project has a harness 
 which reads test specification files and run tests. 
 The tests are usually simple scenarios like 
 "compile and run" or "compile expecting error", 
 but may involve multiple files, incremental compilation, 
 classpath or aspectpath entries, etc.
 This document shows how to write tests that can be run
 by the harness and suggests some patterns to use in
 test code, discussing

 <ul>
  <li><a href="#simple">Simple test definitions</a></li>
  <li><a href="#sourceFiles">Test source files</a></li>
  <li><a href="#incremental">Incremental tests</a></li>
  <li><a href="#verifying">Verifying test steps</a></li>
     <ul>
     <li><a href="#messages">Messages</a></li>
     <li><a href="#dirchanges">Changes in an output directory</a></li>
     <li><a href="#tester">Runtime behavior</a></li>
     </ul>
  <li><a href="#compilerOptions">Compiler Options</a></li>
  <li><a href="#background">Harness background</a></li>
 </ul>
 Most people just writing a test case need to know only the
 information in 
  <a href="#simple">Simple test definitions</a> and 
  <a href="#sourceFiles">Test source files</a>.

 <p>Related documents:
 <ul>
  <li>For information on running the harness, see
      <a href="readme-tests-module.html">
               readme-tests-module.html</a>
    </li>
  <li>For example test definition files, see
      <a href="ajcTests.xml">ajcTests.xml</a> and 
      <a href="ajcTestsFailing.xml">ajcTestsFailing.xml</a>.
    </li>
 </ul>

 <a name="simple"></a>
 <h4>Simple Test definitions</h4>

 Here is a simple example to compile <code>Main.java</code>
 and expect an error on line 10:
 <pre>
    &lt;ajc-test dir="new" title="simple error test">
        &lt;compile files="Main.java">
            &lt;message kind="error" line="10"/>
        &lt;/compile>
    &lt;/ajc-test>
 </pre>

 <p>Here is an example to compile 
 <code>pack/Aspect.java</code> and 
 <code>pack2/Main.java</code> and 
 run the main class:
 <pre>
    &lt;ajc-test dir="new" title="simple run test">
        &lt;compile files="pack/Aspect.java,pack1/Main.java"/>
        &lt;run class="pack1.Main"/>
    &lt;/ajc-test>
 </pre>
 The compile and run steps of a given ajc-test share a common
 sandbox, so (e.g.,) the run step knows to set its classpath using
 the classes directory generated by the compile step.

 <p>More complex compilations are discussed in
   <a href="#compilerOptions">Compiler Options</a> below.

 <a name="sourceFiles"></a>
 <h4>Test source files</h4>

 The <code>dir</code> attribute in the <code>ajc-test</code>
 element specifies a base test directory
 relative to the directory of the test specification file.
 All paths are specified relative to this base test directory.

 E.g., the last example used <code>dir="new"</code> and
 presumed the following directory structure:
 <pre>
    {some dir}                  # test specification directory
        {testDefinition}.xml
        new/                    # test base directory
          pack/Aspect.java
          pack2/Main.java
 </pre>
 Test cases with only one file in the default package can often
 share directories (e.g., see the many files in <a href="new">new/</a>),
 but usually a test case has its own directory.

 <a name="incremental"></a>
 <h4>Incremental tests</h4>    

 Incremental tests are more complex because they involve 
 updating source files before recompiling. 
 Here's an example that
 <ul>
         <li>compiles Main.java,
    </li><li>runs it,
    </li><li>updates the source to introduce an error,
    </li><li>incrementally compile it (and detect the error)
    </li><li>updates the source to fix the error,
    </li><li>incrementally compile it (successfully), and
    </li><li>runs it again.
    </li>
 </ul>
 <pre>
    &lt;ajc-test dir="new/incremental1" title="incremental test">
        &lt;compile staging="true"
                   files="Main.java,DeleteMe.java"/>
        &lt;run class="Main"/>
        &lt;inc-compile tag="20">
            &lt;message kind="error" line="15">
        &lt;/inc-compile>
        &lt;inc-compile tag="30"/>
        &lt;run class="Main"/>
    &lt;/ajc-test>
 </pre>
 Take particular note of two attributes, 
 <code>compile</code>'s "<code>staging</code>"
 and <code>inc-compile</code>'s "<code>tag</code>".
 First, the compile task enables staging, which copies the
 test source files to a temporary directory so they can be
 updated during the test without changing the actual sources.
 Second, incremental compiles specify a tag which identifies
 files to be deleted or copied into the test source staging directory 
 before recompiling. The tag is a suffix identifying
 files in the test source directory specifying how the sources should
 be changed before that incremental compilation step.  
 If there is a prefixing suffix "delete", then the file is deleted;
 otherwise, the file is copied (with the effect either of updating
 an existing file or adding a new file).

 <p>
 Thus, to understand what's happening in an incremental test
 requires comparing the tags with the files specified in
 the test source directory.
 For example, here is a directory layout for the test above:
 <pre>
    {some dir}
        {testDefinition}.xml
        new/
          incremental1/
            DeleteMe.delete.30.java
            DeleteMe.java
            Main.20.java
            Main.30.java
            Main.java
            NewFile.30.java
 </pre>
 The result will be one compile and two re-compiles:
 <ol>
  <li>Compile Main.java and DeleteMe.java</li>
  <li>Update Main.java with the contents of Main.20.java
      and recompile </li>
  <li>Delete DeleteMe.java, 
      add NewFile.java,
      update Main.java with the contents of Main.30.java
      and recompile</li>
 </ol>

 <a name="verifying"></a>
 <h4>Verifying test steps</h4>
 As seen above, two ways to verify that a compile was successful 
 are to run the corresponding class or check the compiler messages. 
 More generally, the harness can verify compile/run test steps by detecting the 
 following things and comparing against expected behavior:
 <p>

 <table border="1" cellpadding="1">

 <tr><th>Detect </th>
    <th>Evaluate</th>
  </tr>
 <tr><td>Exceptions </td>
    <td>signal failure </td>
  </tr>

 <tr><td>Result value </td>
    <td>heuristically compare with expected: 
        compiles not expecting errors are expected 
        to return a normal result status, and vice-versa.</td>
  </tr>
 <tr><td>Messages (e.g., compiler warnings and errors)</td>
    <td>Compare with expected messages</td>
  </tr>

 <tr><td>Directory changes (e.g., <code>.class</code> files created) </td>
    <td>Compare with expected changes</td>
  </tr>
 <tr><td>Runtime behavior</td>
    <td>Use <code>Tester</code> in test source code
       to signal events for comparison with expected events.</td>
  </tr>
 </table>
 <p>

 <a name="messages"></a>
 <h5>Messages</h5>    

 In a test definition, a nested <code>message</code> element 
 specifies a condition on the successful completion of the nesting 
 ajc-test sub-element. In the earlier example, if 
 the harness does not detect an error message on line 10 or if
 there are unexpected messages, then the compile step will be 
 reported as failing:
 <pre>
    &lt;ajc-test dir="new" title="simple error test">
        &lt;compile files="Main.java">
            &lt;message kind="error" line="10"/>
        &lt;/compile>
    &lt;/ajc-test>
 </pre>
 Expected messages can be specified as sub-elements for the three 
  <code>ajc-test</code> elements 
  <code>compile</code>, 
  <code>inc-compile</code>, and 
  <code>run</code>.  
 Messages require a kind (error or warning) and a line.
 To make specification easier, if an error is specified for a line, 
 the harness accepts as expected any number of errors on that line.  
 <p>
 The current harness has only been tested to validate compilation 
 based on line numbers. 
 Filename-based comparison is disabled as untested/unused,
 and run messages are handled wrongly; 
 line-number comparison will fail since
 run messages do not have line numbers.

 <a name="dirchanges"></a>
 <h5>Changes in an output directory</h5>

 As with messages, specifying directory changes as a nested element
 operates as a condition on the successful completion of the
 nesting element.  The harness will check for files added, removed,
 updated, or unchanged from a given directory.  The directory is
 specified explicitly or using a token for the shared classes or
 run directory.  For even more brevity, the harness supports a 
 default suffix for the files.
 <p>
 Directory changes have been used only to validate changes in
 the classes directory.  
 The current harness defaults to using the classes directory,
 and when using the classes directory uses <code>.class</code> 
 as a default suffix.
 <p>
 Here's an example specification:
 <pre>
    &lt;ajc-test dir="new/dirchanges-test" title="dir-changes test">
        &lt;compile staging="true"
                   files="Main.java,DeleteMe.java,Unchanged.java"/>
        &lt;inc-compile tag="20">
            &lt;dir-changes updated="Main" 
                         removed="DeleteMe"
                       unchanged="Unchanged"/>
        &lt;/inc-compile>
    &lt;/ajc-test>
 </pre>
 It checks after a recompile that
 <ul>
  <li><code>Main.class</code> was updated</li>
  <li><code>DeleteMe.class<code> was deleted</li>
  <li><code>Unchanged.class</code> was not touched</li>
 </ul>

 <a name="tester"></a>
 <h5>Runtime behavior</h5>
 Code that tests aspects often falls into the pattern of comparing
 expected and actual events/signals.  For example, to prove that
 before advice in fact ran before a particular method execution,
 you might generated and expect signals corresponding to

 <ol>
  <li>method-call</li>
  <li>before advice execution</li>
  <li>method-execution</li>
 </ol>

 The <code>Tester</code> utility class provides API's for signalling
 actual and expecting events and comparing the two.  
 Typically, events are symbolized and compared as String.
 Here's a small sample test case that for the scenario above:
 <pre>
 import org.aspectj.testing.Tester;

 public class Main implements Runnable {
    public static void main(String[] args) {
        Tester.expectEvent("before advice");
        Tester.expectEvent("execute run");
        new Main().run();     
        Tester.checkAllEvents();
    }
    public void run() {
        Tester.event("execute run");
    }
 }

 aspect A {
    before () : target(Runnable) && execution(void run()) {
         Tester.event("before advice");
    }
 }
 </pre>

 If either the advice or the method does not run,
 the harness will report a failure.

 <p>
 <code>Tester</code> also has methods that operate like 
 JUnit assertions as idioms to detect differences in
 expected and actual values, signalling appropriately.
 <p>

 <code>Tester</code> is at
  <a href="../testing-client/src/org/aspectj/testing/Tester.java">
  ../testing-client/src/org/aspectj/testing/Tester.java</a>
 and is built into 
  <a href="../lib/tests/testing-client.jar">
  ../lib/tests/testing-client.jar</a>
 which is included on the classpath by the compile and run steps.

 <p>You can write runtime test cases without using Tester;
 simply throw some exception from the main thread to signal failure.

 <a name="compilerOptions"></a>
 <h4>Compiler options</h4>
 The harness does not support all of the AspectJ 1.1 compiler options.
 Flags are mainly supported through the a comma-delimited list in
 the <code>options</code> attribute:
 <pre>
    &lt;ajc-test dir="new" title="lint test">
        &lt;compile files="LintTest.java" 
                 options="-Xlint,-emacssym">
            &lt;message kind="warning" line="22">
        &lt;/compile>
 </pre>
 This should work even for complex single-arg options like
 <code>-g:none<code>, but will fail for comma-delimited single-arg options like
 <code>-g:lines,vars</code> because the comma delimiters
 are ambiguous (yes, a design bug!).
 For -source 1.4 and -source 1.3 options,
 use -source14 and -source13 (yes, a hack!). 
 <p>
 The <code>compile</code> element has the following attributes
 which handle most of the other compiler arguments:
 <ul>
        <li><code>files</code>: .aj and .java files are treated as source files,
            but .jar files are extracted and passed to the compiler
            as <code>-injars</code>
   </li><li><code>classpath</code>: directories and jar files for the classpath
   </li><li><code>aspectpath</code>: binary aspects in jar files
   </li><li><code>argfiles</code>: argument list files
   </li>
 </ul>
 Paths for these are all relative to the test base directory, and 
 multiple entries are separated with commas.
 <p>
 Here is a cooked example that uses all <code>compiler</code> attributes:
 <pre>
    &lt;ajc-test dir="new" title="attributes test">
        &lt;compile files="Main.java,injar.jar" 
               staging="true"
               options="-Xlint,-g:none"
              argfiles="debug.lst,aspects/test.lst"
            aspectpath="jars/requiredAspects.jar"
             classpath="providedClassesDir,jars/required.jar"/>
        &lt;inc-compile tag="20"/>
    &lt;/ajc-test>
 </pre>


 <h5>Unsupported compiler options</h5>
 The harness does not support the following AspectJ compiler
 options: -target {version}, -outjar {file}, -sourceroots {dir},
 -log {file}.
 The following are used but specification is not supported:
 -d {dir}, -sourceroots {dir}... 

 <a name="background"></a>
 <h4>Background information on the Harness</h4>
 To make the test specifications as terse as possible,
 harness components for
 <code>inc-compile</code> and <code>run</code> elements
 use information set up earlier by <code>compile</code>,
 some of which is only implicit.  
 When a test is run, the harness creates a staging directory
 for temporary files and a sandbox for sharing information
 between test components, particularly classpath entries
 shared between the compile and run components.  
 The compile and run components share classpath information
 through the sandbox, adding default libraries:
 <ul>
  <li>Aside from any explicit classpath entries,
      <code>compile</code> always includes the jars
      <a href="../lib/tests/aspecjrt.jar">
      ../lib/tests/aspecjrt.jar</a> and 
      <a href="../lib/tests/testing-client.jar">
      ../lib/tests/testing-client.jar</a>
      on the compile classpath.
    </li>
  <li><code>run</code> sets up its classpath as the compile
      classpath plus the compile output (classes) directory
      plus any entries on the aspectpath.
    </li>
 </ul>

 The harness provides some more advance behaviors,
 which you might see specified in the tests.
 For more information, see the API documentation for the harness.
 <ul>
   <li><u>option dominance and overriding</u>:
       Both in test specifications and on the command line
       you can force compiler options on or off.
       These appear in the test specifications as options
       with prefixes
       '!' or '~' rather than '-' (e.g., '~emacssym' to force
       the emacssym option off, even in tests that specify it).
     </li>
 </ul>
 <hr>
 <small>last updated January 7, 2002 </small> <!-- CVS variable -->

 </body>
 </html>