xuechun
/
Migrator.NET


			
				
					
						
						
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        <P class="title">NCover FAQ</P>
        <P>If you have questions that this document does not address, contact <A href="mailto:peter@waldschmidt.com">
                Peter Waldschmidt</A> or try the <A href="http://ncover.org/">NCover Forums</A>.</P>
        <P class="question">1. What is code coverage analysis?</P>
        <P class="answer">A code coverage analyzer monitors your code at runtime and 
            records information about which lines of code were executed. NCover shows each 
            sequence point in your application along with the number of times that point 
            was executed. Sequence points are generated by the compiler and stored in the 
            debug information (.pdb) files. A sequence point basically corresponds to a 
            single program statement (often a line of code) in your high-level language.</P>
        <P class="question">2. Why would I want to do code coverage analysis?</P>
        <P class="answer">Unit test suites are often used as a quality tool during the 
            development process to keep the codebase stable as it changes and expands. 
            Tools such as <A href="http://nunit.org/">NUnit</A> are often used to run and 
            report on the test suites. However, when implementing unit testing in your 
            build process, you have no way of knowing how much of your code the unit tests 
            are actually testing. This is where code coverage comes in. You can run NUnit 
            within NCover and use the code coverage report to determine which code was not 
            tested by that particular test suite.</P>
        <P class="question">3. What versions of the CLR does NCover support?</P>
        <P class="answer">
            NCover 1.5.x requires the .NET framework version 2.0.50727 to be installed; however,
            the application being profiled can be written against any shipping version of the
            framework. NCover
            has been tested profiling coverage of .NET 2.0, .NET 1.1 and .NET 1.0 applications.</P>
        <P class="question">4. Which version of NCover should I install?</p>
        <P class="answer">
            If you have the .NET 2.0 framework installed on your machine then you should use
            the latest NCover version available. NCover as of version 1.5 can profile .NET 2.0, 1.1 and 1.0 applications.</p>
        <p class="answer">
            For development teams who do not have the .NET framework 2.0 installed but do have
            the .NET framework version 1.1.4322, you can
            try NCover 1.3.3. Note however that this version is no longer supported as
            it has a number of known issues and limitations.</p>
        <P class="question">5. What is the command line syntax for NCover?</P>
        <P class="answer">Here is the usage info from the NCover command line (for NCover versions from 1.5.6
            only):</P>
        <pre class="usage">NCover.Console [&lt;command line&gt; [&lt;command args&gt;]]
               [//svc &lt;service name&gt;]
               [//iis]
               [//a &lt;assembly list&gt;]
               [//w &lt;working directory&gt;]
               [//ea &lt;exclusion list&gt;]
               [//reg]
               [//x &lt;xml output file&gt;]
               [//s [&lt;settings file&gt;]] [//r [&lt;settings file&gt;]]
               [//v] [//q] 
               [//l &lt;log file&gt;]

//svc  For profiling windows services
//iis  For profiling web applications

//a    List of assemblies to profile separated by semi-colons i.e. "MyAssembly1;MyAssembly2". Do not include paths or suffixes.
//w    Working directory for profiled application 
//ea   List of attributes marking classes or methods to exclude from coverage 

//reg  Register profiler temporarily for user. (helps with xcopy deployment) 
//x    Specify coverage output file. (default: coverage.xml).
//pm   Specify name of process to profile (i.e. myapp.exe)

//s    Save settings to a file (defaults: NCover.Settings) 
//r    Use settings file, overriding other settings (default: NCover.Settings) 

//l    Specify profiler log file (default: coverage.log).
//q    No logging (quiet) 
//v    Enable verbose logging (show instrumented code)
        </pre>
        <UL>
            <LI>&lt;command line&gt; - This argument specifies the command-line of the .NET application
                you want to analyze. 
                Any command line arguments not starting with // will be passed
                through to that application. NCover will profile the running application until it has exited. See below for examples.<li>//svc - This option is an alternative to the &lt;command line&gt;
                    for profiling windows services, which cannot be run directly as executables. NCover
                    will start the service (stopping it first if already running) and profile coverage
                    until the windows service is stopped.</li>
                <li>//iis - This option is an alternative to the &lt;command line&gt; for profiling
                    web applications. NCover will start the IISAdmin and W3C
                    services (stopping first if currently running) and profile coverage until the IISAdmin
                    service is stopped.<br />
                </li>
            <li>//a - This command-line argument specifies the assemblies that you want to analyze. 
            NCover can only analyze assemblies that have .pdb files included with them. If 
            you do not specify the //a argument, NCover will attempt to analyze every loaded 
            assembly that has debug information available. Note that the assembly name arguments are
                the module name within the assembly, not the physical file name. e.g. "MyAssembly"
                rather than "MyAssembly.dll".<li>//w - If the application being profiled requires the
                    working directory to be set to something other than the current directory you are
                    executing the command line from then you can override it with this argument.</li>
                <li>//ea - You can choose to exclude classes and methods
                    from coverage statistics by defining .NET attribute(s) and applying it to the affected
                    code. When using this argument you must specify the full type namespace of these
                    attribute(s) separated by semi-colons. See below for an example.<br />
                </li>
                <li>//reg - NCover requires a COM registration of the CoverLib.dll assembly containing
                    the profiler, which is performed automatically by the default .msi installation.
                    If you require an xcopy style deployment of NCover like many other .NET tools, then
                    you can use this argument which will temporarily register the profiler while performing
                    coverage. This feature was added in NCover 1.5.6.</li>
                <li>//x - The output of NCover is an xml file (example below). Use this argument to
                    specify an alternate filename to "coverage.xml" in the current directory.<br />
                </li>
                <li>//pm - This setting tells NCover to ignore processes that don't have the specified process module name.
                This is the name of the executable (i.e. myapp.exe).  This setting is useful in cases, where your NCover
                command spawns a series of child processes.  Using this setting will help NCover determine which process to profile.
                </li>
                <li>//s - You may find it more convenient to use a settings file rather than specifying
                    a long list of command line arguments for running NCover. If you get the NCover
                    command line working as you would like it and then use the //s argument it will
                    save the required arguments as an xml file that can then be used by the //r argument
                    below.</li>
                <li>//r - For use when you have used //s to construct an NCover settings file containing
                    your command line arguments. e.g. "ncover.console.exe //r NCover.Settings"<br />
                </li>
                <li>//l - The coverage log file can provide an insight if the desired coverage output
                    is not obtained. Useful information you may find to assist you includes which assemblies
                    were loaded by NCover, their file paths and which of those it found the .pdb build
                    symbols for. Use this argument to specify an alternative log file name or location
                    to coverage.log in the current directory.</li>
                <li>//q - Suppresses writing the coverage.log file.</li>
                <li>//v - This command-line argument makes the profiler emit all the original IL and 
                modified IL instructions to the coverage log. This is useful for debugging 
                purposes. Beware that this can make your coverage log file very large!
            </li>
        </UL>
        <P class="question">6. Does NCover required a special compilation step for my code?</P>
        <P class="answer">No. Some code coverage tools change your source code and force 
            you to recompile it into a special build.&nbsp; NCover is designed to&nbsp;work 
            on shipping code.&nbsp; NCover uses the .NET Framework profiling API to monitor 
            your code. It does require build symbols, but can be run on release code 
            without any modifications.</P>
        <P class="question">7. How does NCover work?</P>
        <P class="answer">NCover uses the .NET Framework profiler API to monitor an 
            application's execution. When a method is loaded by the CLR, NCover retrieves 
            the IL and replaces it with instrumented IL code.&nbsp; NCover does not change 
            your original IL code, it simply inserts new code to update&nbsp;a visit 
            counter at each sequence point.&nbsp; Upon
            request, (usually after the .NET process has shut down) the profiler outputs statistics
            to the coverage file.
        </P>
        <P class="question">
            8. What is the output of NCover?</P>
        <P class="answer">NCover generally writes out three files after analysis 
            completes.
            <ul>
                <li>
                Coverage.log - This file is a log of the events and messages from the profiler 
                during the analysis process. Most of the time, error messages are recorded in 
                this log. If you enable verbose logging, the coverage log will contain 
                disassembly of the original and instrumented IL code.&nbsp; Verbose logging is not recommended for
                    normal use.<li>
                Coverage.xml - This file is the analysis output of NCover. You can see an 
                example of the output below.
                <LI>
                    Coverage.xsl - This file is a simple XML transformation that makes the XML 
                    output easily readable.
                </LI>
            </ul>
            <span class="subtitle">Example XML output</span>
            <div class="box"><pre>&lt;method class="NCoverTest.ClassLoaded" name="HasDeadCode"&gt;
    &lt;seqpnt document="C:\Dev\Utilities\ncover\NCoverTest\NCoverTest.cs"
            column="13" line="48" endcolumn="58" endline="48" visitcount="1" /&gt; 
    &lt;seqpnt document="C:\Dev\Utilities\ncover\NCoverTest\NCoverTest.cs" 
            column="13" line="49" endcolumn="22" endline="49" visitcount="1" /&gt; 
    &lt;seqpnt document="C:\Dev\Utilities\ncover\NCoverTest\NCoverTest.cs" 
            column="17" line="50" endcolumn="24" endline="50" visitcount="1" /&gt; 
    &lt;seqpnt document="C:\Dev\Utilities\ncover\NCoverTest\NCoverTest.cs" 
            column="13" line="51" endcolumn="48" endline="51" visitcount="0" /&gt; 
    &lt;seqpnt document="C:\Dev\Utilities\ncover\NCoverTest\NCoverTest.cs" 
            column="9" line="52"  endcolumn="10" endline="52" visitcount="0" /&gt; 
&lt;/method&gt;</pre>
            </div>
        <p></p>
        <span class="subtitle">Example transformed output</span>
        <div class="box">
            <DIV class="method">NCoverTest.ClassLoaded.HasDeadCode</DIV>
            <TABLE id="Table1" borderColor="black" cellSpacing="0" cellPadding="3" border="1">
                <TBODY>
                    <TR>
                        <TD class="hdrcell">Visit Count</TD>
                        <TD class="hdrcell">Line</TD>
                        <TD class="hdrcell">Column</TD>
                        <TD class="hdrcell">End Line</TD>
                        <TD class="hdrcell">End Column</TD>
                        <TD class="hdrcell">Document</TD>
                    </TR>
                    <TR>
                        <TD class="datacell">1</TD>
                        <TD class="datacell">48</TD>
                        <TD class="datacell">13</TD>
                        <TD class="datacell">48</TD>
                        <TD class="datacell">58</TD>
                        <TD class="datacell">C:\Dev\Utilities\ncover\NCoverTest\NCoverTest.cs</TD>
                    </TR>
                    <TR>
                        <TD class="datacell">1</TD>
                        <TD class="datacell">49</TD>
                        <TD class="datacell">13</TD>
                        <TD class="datacell">49</TD>
                        <TD class="datacell">22</TD>
                        <TD class="datacell">C:\Dev\Utilities\ncover\NCoverTest\NCoverTest.cs</TD>
                    </TR>
                    <TR>
                        <TD class="datacell">1</TD>
                        <TD class="datacell">50</TD>
                        <TD class="datacell">17</TD>
                        <TD class="datacell">50</TD>
                        <TD class="datacell">24</TD>
                        <TD class="datacell">C:\Dev\Utilities\ncover\NCoverTest\NCoverTest.cs</TD>
                    </TR>
                    <TR>
                        <TD class="hldatacell">0</TD>
                        <TD class="datacell">51</TD>
                        <TD class="datacell">13</TD>
                        <TD class="datacell">51</TD>
                        <TD class="datacell">48</TD>
                        <TD class="datacell">C:\Dev\Utilities\ncover\NCoverTest\NCoverTest.cs</TD>
                    </TR>
                    <TR>
                        <TD class="hldatacell">0</TD>
                        <TD class="datacell">52</TD>
                        <TD class="datacell">9</TD>
                        <TD class="datacell">52</TD>
                        <TD class="datacell">10</TD>
                        <TD class="datacell">C:\Dev\Utilities\ncover\NCoverTest\NCoverTest.cs</TD>
                    </TR>
                </TBODY>
            </TABLE>
        </div>
        <P>Suggested usages of the coverage.xml output are to display it in the <a href="http://ncoverexplorer.org/">
                NCoverExplorer</a> gui with the source
        code highlighted, to generate html reports, or to include it in your continuous build server reports such as CruiseControl.Net.
        For more information on these options see below in the FAQ.</P>
        <P></P>
        <P class="question">
            9. How do I use coverage exclusions?</P>
        <p>
            First you should define an attribute to markup your excluded code with. You will
            likely want to put this in a common assembly to make it reusable, or indeed within
            a "CommonAssemblyInfo.cs" that you include in all your application assemblies.</p>
        <P></P>
        <pre class="usage">namespace MyNamespace {
    class CoverageExcludeAttribute : System.Attribute { }
}</pre>
        <p>
            Apply the attribute to the C# classes and/or methods you wish to mark as excluded
            from code coverage statistics:</p>
        <P></P>
        <pre class="usage">    [CoverageExclude]
    private void SomeMethodToExclude() {}    </pre>
        <p>
            Finally, ensure you pass the full qualified attribute information in the NCover command line:</p>
        <P></P>
        <pre class="usage">    NCover.Console MyApplication.exe //ea MyNamespace.CoverageExcludeAttribute    </pre>
        <p>
            Note that if you are using the <a href="http://testdriven.net/">TestDriven.Net</a>
            VS.Net add-in to "Test with Coverage" it will automatically
            pass through "//ea CoverageExcludeAttribute"
            which you should define without a namespace like above. For further information refer to this
            <a href="http://weblogs.asp.net/nunitaddin/archive/2006/10/04/CoverageExclude.aspx">
                blog entry</a>.</p>
        <P class="question">
            10. Examples</P>
        <p>
            Coverage while running a simple executable until it exits:</p>
        <P></P>
        <pre class="usage">    NCover.Console MyApplication.exe</pre>
        <p>
            Coverage while running all the unit tests in an assembly using NUnit, profiling
            all loaded assemblies with .pdb build symbols:</p>
        <P></P>
        <pre class="usage">    NCover.Console nunit-console.exe MyApplication.Tests.dll</pre>
        <p>
            Coverage of only a subset of loaded assemblies while running unit tests:</p>
        <P></P>
        <pre class="usage">    NCover.Console nunit-console.exe MyApplication.Tests.dll //a MyApplication.Core;MyApplication.Utilities</pre>
        <p>
            Coverage of a windows service. Stop the service to generate the coverage output:</p>
        <P></P>
        <pre class="usage">    NCover.Console //svc MyServiceName</pre>
        <p>
            Coverage of an ASP.Net application. Stop the IIS service to generate the coverage
            output:</p>
        <P></P>
        <pre class="usage">    NCover.Console //iis</pre>
        <P class="question">
            11. Where can I get help or support?</P>
        <P class="answer">
            Your best approach is to browse the <a href="http://ncover.org/site/forums/default.aspx">
                NCover forums</a> as well as the <a href="http://ncover.org/SITE/blogs/default.aspx">
                    blog</a> by the author Peter Waldschmidt. If you cannot find a similar issue
            mentioned feel free to post your query and perhaps someone can help.</P>
        <P class="question">
            12. How do I "xcopy deploy" NCover like my other build tools?</P>
        <P class="answer">
            Many developers prefer to have their build tools such as NUnit, NAnt etc stored
            in source control in a Tools folder along with the source code. This ensures that
            a new developer can obtain and build the application without having to install additional
            tools on their own machines.</P>
            <p>
                NCover can also be deployed in this fashion. However the one gotcha with NCover
                versus other tools is that the profiler within CoverLib.dll must be COM registered
                on the local machine before you execute it. Prior to NCover 1.5.6 this was usually
                achieved as part of your build script, which would call regsvr32 with the path to
                the CoverLib.dll in your Tools folder. Alternatively the &lt;ncover&gt; NAnt and
                MSBuild tasks described below will do this for you. As of NCover 1.5.6 you can also
                use the //reg option in the command line arguments which will temporarily register
                the profiler. Note that the //reg option will not work for IIS or Windows Service
                profiling unless you are running NCover under the same Windows login account as
                the IIS worker process, or your Windows Service.</p>
        <P class="question">
            13. How do I see my source code highlighted with the coverage results?</P>
        <P class="answer">
            <a href="http://ncoverexplorer.org/">NCoverExplorer</a> is a gui and console-based
            .NET application developed by <a href="http://www.kiwidude.com/blog/">Grant Drake</a>. NCoverExplorer
            parses the coverage.xml files output from NCover and displays the results integrated
            with your source code. It also includes a number of additional features to merge,
            filter, sort and generate html reports. The console version is
            designed to be used as part of an automated build process. The support forums for
            NCoverExplorer are located with the NCover ones at <a href="http://ncover.org">http://ncover.org/</a>.<strong>&nbsp;</strong></P>
        <P class="question">
            14. How do I run NCover from within the Visual Studio.Net IDE?</P>
        <P class="answer">
            The <a href="http://testdriven.net/">TestDriven.Net</a> add-in by <a href="http://weblogs.asp.net/nunitaddin/">
                Jamie Cansdale</a> offers a right-click capability within the IDE to execute
            your unit tests with code coverage. The results of the NCover code coverage are
            displayed with the bundled NCoverExplorer gui for analysis and reporting.</P>
        <P class="question">
            15. How do I run NCover from a NAnt or MSBuild task?</P>
        <P class="answer">
            You can use an &lt;exec&gt; task with <a href="http://nant.sourceforge.net/">NAnt</a>
            or an &lt;Exec&gt; task with MSBuild. Alternatively you may want to use the custom
            &lt;ncover&gt; task for NAnt or &lt;NCover&gt; task for MSBuild developed by Grant
            Drake for a more developer friendly syntax. The source code, compiled assemblies
            and documentation are located in the NCoverExplorer.Extras.zip available from <a
                href="http://ncoverexplorer.org/">http://ncoverexplorer.org/</a>.</P>
        <P class="question">
            16. How do I include NCover output in my CruiseControl.Net build reports?</P>
        <P class="answer">
            <a href="http://ccnet.thoughtworks.com/">CruiseControl.Net</a> is a continuous integration
            build server which offers web-based reporting of the outputs of a build such as
            unit test results and code coverage reporting. The default CruiseControl.Net installation
            includes a basic stylesheet which works in combination with the standard coverage.xml
            formatted output. So all you need to do is include the execution of NCover as part
            of your build, then add a CruiseControl.Net merge file publisher task to integrate
            the coverage.xml results into the build output.</P>
            <p class="answer">
                An improvement on the above to display more attractive and powerful reports as well
                as minimize the build log size is to use NCoverExplorer. The NCoverExplorer.Console.exe
                is designed to produce a more concise xml report summary that is combined with an
                alternate xsl stylesheet for CruiseControl.Net. You can find more information and
                screenshots in this <a href="http://www.kiwidude.com/blog/2006/04/ncoverexplorer-v133.html">
                    blog entry</a> - all the necessary tasks, examples and documentation are located
                within NCoverExplorer.Extras.zip available from <a href="http://ncoverexplorer.org/">
                    http://ncoverexplorer.org/</a>.&nbsp;</p>
        <P class="question">
            17. How do I merge multiple NCover coverage.xml results?</P>
        <P class="answer">
            You can can use NCoverExplorer to merge the results of multiple coverage runs. For
            more information refer to this <a href="http://www.kiwidude.com/blog/2006/10/ncoverexplorer-merging-ncover-reports.html">
                blog entry</a>.</P>
        <P class="question">
             18. Troubleshooting: Why is my coverage.xml file empty?</P>
            <ul>
                <li>If using the command-line, did you COM register CoverLib.dll (or use the //reg option
                    from NCover 1.5.6)?</li>
                <li>Did you generate build symbol files (.pdbs) for the profiled application?</li>
                <li>If using the //a option, did you correctly list just the assembly names without
                    paths or .dll suffixes?</li>
            </ul>
         <P class="question">
            19. Troubleshooting: I have coverage.xml output but my XYZ assembly is not included in it?</P>
            <ul>
                <li>NCover will only profile loaded assemblies - did your code execution path while
                    under coverage force that assembly to be loaded (e.g. by loading a type or calling
                    a method in that assembly)?&nbsp;</li>
                <li>Did you generate build symbol files (.pdb files) for the missing assembly? </li>
                <li>If using the //a option, did you correctly list the assembly names including the
                    one that is missing?</li>
                <li>Can you see information about the assembly being loaded within the coverage.log?
                    Is the correct assembly being loaded (check the path) - if you have a version in
                    the GAC it may possibly prevent the .pdb file from being loaded.</li><li>If using the NCoverExplorer gui, have you got a coverage exclusion defined which
                    is hiding it from the display?</li>
            </ul>
         <P class="question">
            20. Troubleshooting: After running NCover my coverage.log says "Failed to load symbols for module XYZ"?</P>
            <ul>
                <li>This message means that no .pdb build symbol file was found for that assembly so
                    it cannot be profiled for code coverage. If that assembly is part of the .NET framework
                    for instance like System.Data.dll, then this is an expected message and should not
                    cause concern.&nbsp;</li><li>If however the assembly belongs to your application, did you generate the
      build symbol files (.pdb files) for it? </li>
            </ul>
         <P class="question">
            21. Troubleshooting: I get a "Profiled process terminated. Profiler connection not
             established" message?</P>
            <ul>
                <li>If using the command-line, did you COM register CoverLib.dll (or use the //reg option
                    from NCover 1.5.6)?</li><li>Are you running Windows XP 64-bit? You may want to take a look at
      <a href="http://ncover.org/SITE/forums/thread/43.aspx">this thread</a></li></ul>
         <P class="question">
             22. Troubleshooting: My coverage exclusions are not working?</P>
            <ul>
                <li>Have you put the full namespace type name to the exclusion including the Attribute suffix in the //ea argument? See the "How
                    do I use coverage exclusions?" question above.</li></ul>
           &nbsp;
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