Introduction
Emma is an open source code coverage tool. In our case, Emma enables code coverage by instrumenting the target code. The instrumentation process involves Emma looking at the class or jar files and adding its own layer between the JVM and the code normally called.
During the Instrumenting process, metadata is created per class. This metadata is stored in files locally. In our situation, we generate one meta file per webapp.
The instrumented code has an extra port open, which can accept commands from Emma such as return coverage information or reset coverage information that resides in memory.
To generate a full report Emma requires:
- the code has been compiled with the debug option on
- the source code is available,
- session data is available in a local file,
- a relevant metadata file exists.
Command line recipe
Prerequisite
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h3. Introduction Emma is an open source code coverage tool. In our case, Emma enables code coverage by instrumenting the target code. The instrumentation process involves Emma looking at the class or jar files and adding its own layer between the JVM and the code normally called. During the Instrumenting process, metadata is created per class. This metadata is stored in files locally. In our situation, we generate one meta file per webapp. The instrumented code has an extra port open, which can accept commands from Emma such as return coverage information or reset coverage information that resides in memory. *To generate a full report Emma requires:* # the code has been compiled with the debug option on # the source code is available, # session data is available in a local file, # a relevant metadata file exists. h3. Command line recipe h4. Prerequisite * The highest version (build 2.1.5320) emma jar file needs to be downloaded from [Emma home| http://emma.sourceforge.net]. The jar needs to be placed in {$JAVA_HOME}/jre/lib/ext or added to the classpath of the following commands. This is also true for the JAVA_HOME seen by the Sakai server. |
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* the source code is available for report generation |
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*Note:* I have written a simple Perl script that copies all the source code into one directory |
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structure instead of being scattered under the java/src directories. This allows report generation for all reports to point to the same source code directory. |
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* Javac compiles the source code with debug option on |
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*Note:* Running maven pack-demo compiles with debug on by |
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Instrument code
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default h4. Instrument code Once emma.jar sits in the appropriate directory then the following command should bring up the help information for EMMA: |
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{$JAVA_HOME}/bin/java emma |
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{code | ||||
:title | =Resulting output | |borderStyle | =solid | } emma usage: emma <command> command options, where <command> is one of: run application runner same as 'emmarun' tool; instr offline instrumentation processor; ctl remote control processor; merge offline data file merge processor. report offline report generator; use '<command> -h' to see usage help for a given command EMMA v2.1, build 5320 (stable) |
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{code} *Note 1:* Any older version than that mentioned in the results will not function correctly for our needs. |
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*Note 2:* I have written some example only Perl code that looks for Web-INF/classes directories and |
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then generates a [bash script|http://issues.sakaiproject.org/confluence/download/attachments/32346/inst.sh] that runs Emma and generates a metadata file, one per Webapp |
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Assuming you are running from a *NIX environment and the now standard bash environment and the target Sakai server has been shutdown. |
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{code |
} java emma instr -ix - -ip {$SAKAI_HOME}/webapps/{$EMMA_INST}/WEB-INF/classes -m overwrite -out= {$EMMA_REPORT_HOME}/{$EMMA_INST}.em |
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Variable
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Description
{code} |*Variable*|*Description*| |SAKAI_HOME |
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| File location of the root of your Sakai Server |
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| |EMMA_REPORT_HOME |
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|File location for root dir for report generation |
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| |EMMA_INST |
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|Webapp to instrument. E.G.: sakai-login-tool |
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| *Result:* The code for the sakai-login-tool is now instrumented and a metadata file sakai-login-tool.em has been created in the report directory. |
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Otherwise, you will need to expand the variables and add the full paths. h4. |
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Generate report |
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Restart your server. |
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Near the beginning of the logging you will see an entry mentioning Emma is alive and listening at a given port number. |
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*Collect session data and reset in memory data |
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{code}
java emma ctl -connect localhost:47653 -command coverage.get,{$EMMA_REP0RT_HOME}/coverage.ec -command coverage.reset
{code}
*Generate the actual report:*
mkdir {$EMMA_REP0RT_HOME}/{$EMMA_INST}.
java emma report -r html -sp ${EMMA_SRC_DIR} -in {$EMMA_REP0RT_HOME}/{$EMMA_INST}.em/coverage_demo.em -in -Dreport.html.out.file={$EMMA_REP0RT_HOME}/{$EMMA_INST}/index.html |