Update test framework: fix run_tests.py to support all test files, add auto-import-check for test files

node_modules/throttleit/index.js

@@ -0,0 +1,30 @@
+function throttle(function_, wait) {
+	if (typeof function_ !== 'function') {
+		throw new TypeError(`Expected the first argument to be a \`function\`, got \`${typeof function_}\`.`);
+	}
+
+	// TODO: Add `wait` validation too in the next major version.
+
+	let timeoutId;
+	let lastCallTime = 0;
+
+	return function throttled(...arguments_) { // eslint-disable-line func-names
+		clearTimeout(timeoutId);
+
+		const now = Date.now();
+		const timeSinceLastCall = now - lastCallTime;
+		const delayForNextCall = wait - timeSinceLastCall;
+
+		if (delayForNextCall <= 0) {
+			lastCallTime = now;
+			function_.apply(this, arguments_);
+		} else {
+			timeoutId = setTimeout(() => {
+				lastCallTime = Date.now();
+				function_.apply(this, arguments_);
+			}, delayForNextCall);
+		}
+	};
+}
+
+module.exports = throttle;