Better validation in test-each

test/helpers/test_each/input.js

@@ -1,13 +1,24 @@
 // Parse and validate main input
 export const parseInput = function(inputArgs) {
   const iterables = inputArgs.slice(0, -1)
+  iterables.forEach(validateIterable)
 
   const func = inputArgs[inputArgs.length - 1]
   validateFunc(func)
 
   return { iterables, func }
 }
 
+const validateIterable = function(iterable) {
+  if (iterable[Symbol.iterator] === undefined && !isRepeat(iterable)) {
+    throw new TypeError(`Argument must be an iterable or a positive integer: ${iterable}`)
+  }
+}
+
+export const isRepeat = function(iterable) {
+  return Number.isInteger(iterable) && iterable >= 0
+}
+
 const validateFunc = function(func) {
   if (typeof func !== 'function') {
     throw new TypeError(`Last argument must be a function: ${func}`)