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 Chai Assertion Library Regex Cheat Sheet Postman: The Complete Guide on Udemy