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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
- The highest version (build 2.1.5320) emma jar file needs to be downloaded from Emma home. The jar needs to be placed in {$JAVA_HOME}/jre/lib/ext
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- or
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- added
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- to
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- the
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- classpath
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- of
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- the
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- following
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- commands.
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- This
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- is
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- also
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- true
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- for
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- the
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- JAVA_HOME
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- seen
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- by
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- the
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- Sakai
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- server.
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- the
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- source
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- code
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- is
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- available
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- for
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- report
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- generation
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Note:
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- I
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- have
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- written
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- a
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- simple
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- Perl
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- script
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- that
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- copies
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- all
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- the
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- source
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- code
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- into
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- one
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- directory
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structure
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- instead
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- of
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- being
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- scattered
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- under
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- the
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- java/src
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- directories.
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- This
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- allows
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- report
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- generation
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- for
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- all
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- reports
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- to
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- point
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- to
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- the
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- same
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- source
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- code
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- directory.
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- Javac
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- compiles
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- the
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- source
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- code
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- with
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- debug
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- option
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- on
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Note:
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- Running
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- maven
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- pack-demo
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- compiles
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- with
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- debug
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- on
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- by
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- default
Instrument code
Once emma.jar
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sits
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in
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the
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appropriate
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directory
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then
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the
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following
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command
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should
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bring
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up
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the
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help
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information
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for
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EMMA:
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{$JAVA_HOME}/bin/java
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emma
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| Code Block | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| =
|
| |
| =
| }||||||||||
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)
{code}
*Note |
Note 1:
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Any
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older
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version
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than
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that
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mentioned
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in
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the
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results
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will
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not
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function
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correctly
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for
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our
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needs.
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Note
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2:
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I
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have
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written
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some
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example
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only
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Perl
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code
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that
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looks
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for
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Web-INF/classes
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directories
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and
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then
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generates
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a
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...
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that
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runs
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Emma
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and
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generates
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a
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metadata
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file,
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one
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per
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Webapp
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Assuming
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you
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are
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running
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from
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a
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*NIX
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environment
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and
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the
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now
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standard
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bash
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environment
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and
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the
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target
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Sakai
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server
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has
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been
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shutdown.
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| Code Block |
|---|
java emma instr -ix - -ip {$SAKAI_HOME}/webapps/{$EMMA_INST}/WEB-INF/classes -m overwrite
-out= {$EMMA_REPORT_HOME}/{$EMMA_INST}.em
{code}
|*Variable*|*Description*|
| |
Variable | Description |
SAKAI_HOME |
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File |
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location |
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of |
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the |
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root |
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of |
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your |
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Sakai |
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Server |
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EMMA_REPORT_HOME |
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File |
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location |
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for |
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root |
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dir |
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for |
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report |
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generation |
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EMMA_INST |
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Webapp |
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to |
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instrument. |
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E.G.: |
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sakai-login-tool |
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Result:
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The
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code
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for
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the
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sakai-login-tool
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is
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now
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instrumented
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and
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a
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metadata
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file
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sakai-login-tool.em
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has
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been
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created
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in
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the
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report
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directory.
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Otherwise,
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you
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will
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need
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to
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expand
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the
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variables
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and
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add
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the
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full
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paths.
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Generate
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report
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Restart
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your
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server.
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Near
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the
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beginning
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of
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the
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logging
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you
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will
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see
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an
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entry
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mentioning
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Emma
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is
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alive
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and
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listening
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at
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a
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given
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port
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number.
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Collect
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session
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data
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and
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reset
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in
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memory
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data:
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| Code Block |
|---|
java emma ctl -connect localhost:47653 -command coverage.get,{$EMMA_REP0RT_HOME}/coverage.ec -command coverage.reset
{code}
*Generate the actual report:*
mkdir |
Generate the actual report:
mkdir {$EMMA_REP0RT_HOME}/{$EMMA_INST}
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java
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emma
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report
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-r
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html
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-sp
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{
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$EMMA_SRC_DIR}
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-in
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{$EMMA_REP0RT_HOME}/{$EMMA_INST}.em/coverage_demo.em
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-in
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-Dreport.html.out.file={$EMMA_REP0RT_HOME}/{$EMMA_INST}/index.html