improve error message

src/lib/grandExchange.ts

@@ -766,9 +766,14 @@ ${type} ${toKMB(quantity)} ${item.name} for ${toKMB(price)} each, for a total of
 
 		debugLog(`Expected G.E Bank: ${shouldHave}`);
 		if (!currentBank.equals(shouldHave)) {
-			throw new Error(
-				`GE either has extra or insufficient items. Difference: ${shouldHave.difference(currentBank)}`
-			);
+			if (!currentBank.has(shouldHave)) {
+				throw new Error(
+					`GE is MISSING items to cover the ${
+						[...buyListings, ...sellListings].length
+					}x active listings. Difference: ${shouldHave.difference(currentBank)}`
+				);
+			}
+			throw new Error(`GE has EXTRA items. Difference: ${shouldHave.difference(currentBank)}`);
 		} else {
 			debugLog(
 				`GE has ${currentBank}, which is enough to cover the ${

tests/integration/grandExchange.test.ts

@@ -62,6 +62,12 @@ describe('Grand Exchange', async () => {
 	GrandExchange.calculateSlotsOfUser = async () => ({ slots: 500 } as any);
 	await mockClient();
 
+	async function waitForGEToBeEmpty() {
+		await GrandExchange.queue.onEmpty();
+		assert(GrandExchange.queue.size === 0, 'G.E Queue should be empty');
+		assert(!GrandExchange.locked, 'G.E should not be locked');
+	}
+
 	test(
 		'Fuzz',
 		async () => {
@@ -84,6 +90,7 @@ describe('Grand Exchange', async () => {
 			}
 			console.log(`Finished initializing ${amountOfUsers} users`);
 
+			// Run a bunch of commands to buy/sell
 			const commandPromises = new PQueue({ concurrency: 10 });
 			for (const user of shuffleArr(users)) {
 				const method = randArrItem(['buy', 'sell']);
@@ -101,33 +108,34 @@ describe('Grand Exchange', async () => {
 					}
 				});
 			}
-
 			await commandPromises.onEmpty();
-			await GrandExchange.queue.onEmpty();
+			await waitForGEToBeEmpty();
 
 			console.log('Finished running all commands');
 
+			// Tick the g.e to make some transactions
 			for (let i = 0; i < 100; i++) {
 				await GrandExchange.tick();
 				await Promise.all([
 					GrandExchange.checkGECanFullFilAllListings(),
 					GrandExchange.extensiveVerification()
 				]);
 			}
+			await waitForGEToBeEmpty();
 			console.log('Finished ticking 100 times');
 
-			const testBank = new Bank();
+			// Cancel all remaining listings
 			const cancelPromises = [];
 			for (const user of users) {
 				cancelPromises.push(cancelAllListings(user));
 			}
-
 			await Promise.all(cancelPromises);
-			await GrandExchange.queue.onEmpty();
+			await waitForGEToBeEmpty();
 			console.log('Finished cancelling');
 
 			await Promise.all(users.map(u => u.sync()));
 
+			const testBank = new Bank();
 			for (const user of users) {
 				testBank.add(user.bankWithGP);
 			}