The test verifies functionality of protocol method CSS.setStyleTexts for @page.
==== Initial style sheet text ====
article {
  color: blue;
}

@page {
  size: 8.5in 9in;
  margin-top: 4in;
}

#test {
  background-color: grey;
}


Running test: testCanChangeAtPage
ERROR: Failed applying edit #0: NotFoundError Source range didn't match existing style source range
Dumping matched rules: 
*article* {    regular
    color: blue; @[1:2-1:14]
    color: blue; @[undefined-undefined]
}
*#test* {    regular
    background-color: grey; @[10:2-10:25]
    background-color: grey; @[undefined-undefined]
}
Dumping inherited rules: 

Running test: testCanChangeRulesBefore
==== Style sheet text ====
article {
  color: green;
}

@page {
  size: 8.5in 9in;
  margin-top: 4in;
}

#test {
  background-color: grey;
}

Dumping matched rules: 
*article* {    regular
    color: green; @[1:2-1:15]
    color: green; @[undefined-undefined]
}
*#test* {    regular
    background-color: grey; @[10:2-10:25]
    background-color: grey; @[undefined-undefined]
}
Dumping inherited rules: 

Running test: testCanChangeRulesAfter
==== Style sheet text ====
article {
  color: blue;
}

@page {
  size: 8.5in 9in;
  margin-top: 4in;
}

#test {
  background-color: blue;
}

Dumping matched rules: 
*article* {    regular
    color: blue; @[1:2-1:14]
    color: blue; @[undefined-undefined]
}
*#test* {    regular
    background-color: blue; @[10:2-10:25]
    background-color: blue; @[undefined-undefined]
}
Dumping inherited rules: