# Testing With Postman: Checking Schema

Schema is something you need to test to make sure when they need a string that it is indeed a string. If you google postman and schema checking you will also find a cool tool called tv4. Do not use this as it is out dated and no longer supported. Please just create a test like below. Also create the jsonData inside the test so it bombs out a single test and not the whole collection when running.

```
pm.test("Has correct schema", function() {
     let jsonData = pm.response.json()
     pm.expect(jsonData.str).to.be.a("string", "str not a string and instead is " + jsonData.str);
     pm.expect(jsonData.numArray[0]).to.be.a("number", "numArray[0] not a number and instead is " + jsonData.numArray[0]);
     pm.expect(jsonData.numArray[1]).to.be.a("integer", "numArray[1] not a integer and instead is " + jsonData.numArray[1]);
     pm.expect(jsonData.bool).to.be.a("boolean", "bool not a boolean and instead is " + jsonData.bool);
});
``` 

You can also output to the console if you would like something added to the log. Below are the different ways you can log to the console. 

console.log(); outputs log messages to console
console.info(); outputs information messages to console
console.warn(); outputs warning messages to console
console.error(); outputs error messages to console

An example is if you are calling a string object instead of a string. There is no or in Chai so you will need to use the below code.


```
pm.expect(jsonData.stringObject).to.be.to.satisfy(function(s){
      return s === null || typeof s == 'string'
}, "stringObject is not a string or null")
``` 
# Links
[Postman Quick Reference Guide](https://postman-quick-reference-guide.readthedocs.io/en/latest/index.html)
[Chai Assertion Library](https://www.chaijs.com/api/bdd/)
[Regex Cheat Sheet](https://www.rexegg.com/regex-quickstart.html)
[Postman: The Complete Guide on Udemy](https://www.udemy.com/postman-the-complete-guide/)