New rule: AvoidMixingJunit4AndJunit5

[dgroup]

Summary

Key	Value
Rule	AvoidMixingJunit4AndJunit5
Ruleset	io/github/dgroup/arch4u/pmd/testing/junit.xml
Category	Error Prone
Framework	junit
Since	TBD
Incidents in past at my experience	4+
Template	false

Rule definition

<rule name="..."
      since="0.2.0"
      language="java"
      externalInfoUrl="https://github.com/dgroup/arch4u-pmd/discussions/..."
      message="...: https://github.com/dgroup/arch4u-pmd/discussions/..."
      class="io.github.dgroup.arch4u.pmd....">
    <priority>3</priority>
    <properties>
      <property name="..." delimiter="|" value="...|...|...|..."/>
      <property name="..." value="...|..."/>
    </properties>
</rule>

Why?

...

@org.junit.jupiter.api.extension.ExtendWith(Xxx.class) // junit5 class
class MyTest {

    @org.junit.Test // junit4 class, violation
    public void justTestIt(){
         ...
    }
    
}

This approach might be useful:

1. By XPath detect junit5 classes
   and by regexp XPath detect junit4 classes

//Name[starts-with(@Image, 'org.junit.')] and //Name[starts-with(@Image, 'org.junit.jupiter.')]

String expr = "//*[regexp:test(@id, 'sometext[0-9]+_text')]";
driver.findElement(By.xpath(expr));