whereGrade method
Creates a WidgetSelector that finds all Icon where grade matches the condition.
Example usage:
spot<Icon>().whereGrade((it) => it.isGreaterThan(10.5)).existsOnce();
Implementation
@useResult
WidgetSelector<Icon> whereGrade(MatchProp<double> match) {
return withDiagnosticProp<double>('grade', match);
}