Regular Expressions: QA Challenge Accepted Conf (March 2015)
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Regular Expressions … and Their Place in the QA Engineer's Life Svetlin Nakov Manager Training and Inspiration Software University http://softuni.bg
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Transcript of Regular Expressions: QA Challenge Accepted Conf (March 2015)
Regular Expressions
… and Their Place in the QA Engineer's Life
Svetlin Nakov
Manager Trainingand Inspiration
Software University
http://softuni.bg
What are Regular Expressions?
• Regular expressions (regex)
– Match text by pattern
• Patterns are defined by special syntax, e.g.
– [0-9]+ matches non-empty sequence of digits
– [A-Z][a-z]* matches a capital + small letters
– \s+ matches whitespace (non-empty)
• \S+ matches non-whitespace
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More Patterns
• \d+ matches digits
– \D+ matches non-digits
• \w+ matches letters (Unicode)
– \W+ matches non-letters
• \+\d{1,3}([ -]*[0-9]){6,} matches
international phone, e.g. +359 2 123-456
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Validation by Regex
• ^ matches start of text
• $ matches end of text
• ^\+\d{1,3}([ -]*[0-9]){6,}$ validates
international phone
• +359 2 123-456 is a valid phone
• +359 (888) 123-456 is a invalid phone
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Regex Literals
• The classical (Perl syntax) is:
– /<regex>/<options>
• Examples:
– /[a-z]+/gi matches all non-empty sequences
of Latin letters, case-insensitively
– /[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,20}/gi matches emails (simplified pattern)
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Some JS Code: Validation
var emailPattern =
/^[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,20}$/i;
console.log(emailPattern.test("[email protected]"));
console.log(emailPattern.test("[email protected]"));
console.log(emailPattern.test("invalid@@mail"));
console.log(emailPattern.test("err [email protected]"));
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Some JS Code: Split
var towns = "Sofia, Varna,Pleven, Veliko Tarnovo; Paris – London––Viena\n\n Пловдив|Каспичан";
console.log(towns.split(/\W+/)); // incorrect
console.log(towns.split(/\s*[.,|;\n\t–]+\s*/));
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Some JS Code: Match
var text = "I was born at 14-Jun-1980. Today is 14-Mar-2015. Next year starts at 1-Jan-2016 and ends at 31-Dec-2016.";
var dateRegex = /\d{1,2}-\w{3}-\d{4}/gm;
console.log(text.match(dateRegex));
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Regex for QA Engineers
• Why should a QA understand regex?
– Validation prepare regex for developers
– Write automation testing scripts
• E.g. find a text on the page by regex
– Parse a text, extract info, split data, …
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Resources
• Play with regex:
– http://www.regexr.com
– https://regex101.com
• Visual regex debugger:
– https://www.debuggex.com
• Regex explained (in Bulgarian)
– http://goo.gl/NbBIPe
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Resources (2)
• Interactive Regex Tutorial
– http://regexone.com
• Regex @ W3Schools
– http://w3schools.com/jsref/jsref_obj_regexp.asp
• Regex Tutorial (for Java)– vogella.com/tutorials/JavaRegularExpressions/article.html
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Regular Expressions
Questions?
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