I found it.
it related to setting of PHPUnit. i create a file and renamed it to phpunit.xml and put following configuration code to it.
<phpunit backupGlobals="false"
backupStaticAttributes="false"
colors="true"
convertErrorsToExceptions="true"
convertNoticesToExceptions="true"
convertWarningsToExceptions="true"
processIsolation="false"
stopOnFailure="false"
syntaxCheck="false"
>
<testsuites>
<testsuite name="Package Test Suite">
<directory suffix=".php">./tests/</directory>
</testsuite>
</testsuites>
</phpunit>
and after a ran phpunit for create local coverage.xml file; it given to me following error:
Error: No code coverage driver is available
and i after a little search it found i have to insert following code into phpunit.xml
<filter>
<whitelist processUncoveredFilesFromWhitelist="true">
<directory suffix=".php">src</directory>
</whitelist>
</filter>
so final phpunit.xml file is
<?xml version="1.0" encoding="UTF-8"?>
<phpunit backupGlobals="false"
backupStaticAttributes="false"
colors="true"
convertErrorsToExceptions="true"
convertNoticesToExceptions="true"
convertWarningsToExceptions="true"
processIsolation="false"
stopOnFailure="false"
syntaxCheck="false"
>
<testsuites>
<testsuite name="Package Test Suite">
<directory suffix=".php">./tests/</directory>
</testsuite>
</testsuites>
<filter>
<whitelist processUncoveredFilesFromWhitelist="true">
<directory suffix=".php">src</directory>
</whitelist>
</filter>
</phpunit>