avoid calling Util.mkString with associative array (#3)

czenker · Dec 31, 2017 · 1ab9ca4 · 1ab9ca4
1 parent c79ba8f
commit 1ab9ca4
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Showing 2 changed files with 8 additions and 3 deletions.
diff --git a/src/lively_epsilon/util.lua b/src/lively_epsilon/util.lua
@@ -77,6 +77,10 @@ Util = {
     end,
 
     mkString = function(table, separator, lastSeparator)
+        if not Util.isNumericTable(table) then
+            error("The given table needs to have numerical indices.", 2)
+        end
+
         local string = ""
 
         local lastIndex = 0
@@ -90,7 +94,6 @@ Util = {
                 string = string .. value
                 isFirst = false
             else
-                local nextKey, nextValue = next(table)
                 if k == lastIndex and lastSeparator ~= nil then
                     -- if last element
                     string = string .. lastSeparator .. value

diff --git a/test/util_spec.lua b/test/util_spec.lua
@@ -158,10 +158,12 @@ insulate("Util", function()
                 assert.equal(Util.mkString(table, ", ", " and "), "one, two and three")
             end)
 
-            it("should return a string for three values when using an indexed table", function()
+            it("should fail when using an associative table", function()
                 local table = { a = "one", c = "two", b = "three" }
 
-                assert.equal(Util.mkString(table, ", ", " and "), "one, two and three")
+                assert.has_error(function()
+                    Util.mkString(table, ", ", " and ")
+                end)
             end)
         end)