LetsTest - Naive Test "framework"

LetsTest.js

( function __LetsTest__install(){

	window.LetsTest = window.LetsTest || {};

	function that( toBeChecked ){
		var myret;
		
		if ( toBeChecked instanceof Function ) 
			myret = toBeChecked();
		else
			myret = toBeChecked;
		
		return {
			ret: myret,
			is: is
		}
	};

	function is( val ){
		var passed = ( this.ret === val );
		var typeMismatch = !passed && ( this.ret == val );

		if ( typeMismatch )
			console.warn( "Type mismatch!" );

		if ( passed )
			console.log( "Test passed" );
		else
			console.warn( "Test failed, expecting", 
							typeof this.ret, this.ret, 
						  "but had", 
						  	typeof val, val );
		return passed;
	
	}

	if ( !window.LetsTest.that || !( window.LetsTest.that instanceof Function ) ) {
		window.LetsTest.that = that;
	}
	
} )();

LetsTest.that( 42 ).is( 42 ) // true
LetsTest.that( () => 42 ).is( 42 ) // true