Low budget unit tests instead of Jasmine or Chai. Isolates between invocations. Safely contains everything that can go wrong.

unitTest.ts

export default function unitTest (description:string, testFunction:Function):void {
	const testLog:Array<string> = [`Test: ${description}:`];
	const expectQueue:Array<Function> = [];
	class Expectation {
		actualValue;
		constructor(anyValue: any) {
			this.actualValue = anyValue;
			return this;
		}
		toBe(expectedValue: any) {
			expectQueue.push(():void => {
				if(expectedValue !== this.actualValue)
					throw new Error(`Expected value "${expectedValue}" but received value "${this.actualValue}" instead.`);
			});
		}
	}
	function expect(anyValue: any):Expectation {
		return new Expectation(anyValue);
	}
	let caughtError = false;
	let startTime:number = performance.now();
	let totalTime:string;
	try {
		testFunction(expect);
		totalTime = (performance.now() - startTime).toFixed(3);
		if(expectQueue.length === 0) {
			testLog.push("	❓ Tests FAILED: No expectations were defined.");
			process.exitCode = 1;
			caughtError = true;
		}
	} catch (error) {
		totalTime = (performance.now() - startTime).toFixed(3);
		testLog.push(`	❌ Tests FAILED in ${totalTime}ms.: ${error}\n		${error.stack.replaceAll("    ", "		  ")}`);
		process.exitCode = 1;
		caughtError = true;
	}
	let totalExp = 0;
	for(const exp of expectQueue) {
		try {
			totalExp++;
			exp();
		} catch (error) {
			testLog.push(`	❌ Tests FAILED in ${totalTime}ms.\n	❌ Expectation #${totalExp} FAIL: ${error.toString()}`);
			process.exitCode = 1;
			caughtError = true;
		}
	}
	if(!caughtError)
		testLog.push(`	🟢 Tests PASSED in ${totalTime}ms.`);
	console.log(testLog.join("\n") + "\n");
}