salesforce

equality

String comparison using == is case-insensitive

Docs

Also, Apex and SOQL are case-insensitive so the following are both valid, and the same;

list<something> = [select Id from something];
List<Something> = [SELECT id FROM Something];

limits

(Non-SObject) constructors are limited to having 32 arguments, workaround by wrapping parameters in other objects.
Apex classes are limited to 1 million characters
Apex total character count (minus comments) is limited to 6 million
Standard object limits
Scratch org limits

links

testing

Queue tests via command prompt using SFDX;

sfdx force:apex:test:run --resultformat human --outputdir c:\wherever --loglevel error --classnames MyFirstTest,MySecondTest

Get the detail on a previous test run;

sfdx force:apex:test:report -i <job-id>

Docs