1 files changed, 15 insertions, 12 deletions

diff --git a/spec/02-random_spec.lua b/spec/02-random_spec.lua
index db5d5ce..7b2eea6 100644
--- a/spec/02-random_spec.lua
+++ b/spec/02-random_spec.lua
@@ -155,24 +155,27 @@ describe("Random:", function()
     end)
 
 
-    it("returns nil and error for empty interval (m > n)", function()
-      local v, err = system.rnd(10, 5)
-      assert.is_falsy(v)
-      assert.are.equal("interval is empty", err)
+    it("throws for empty interval (m > n), like math.random", function()
+      local ok_math, _ = pcall(math.random, 10, 5)
+      assert.is_falsy(ok_math, "math.random(10, 5) should error")
+      local ok_rnd, _ = pcall(system.rnd, 10, 5)
+      assert.is_falsy(ok_rnd, "rnd(10, 5) should throw like math.random")
     end)
 
 
-    it("returns nil and error for invalid one-arg (m < 1, m ~= 0)", function()
-      local v, err = system.rnd(-1)
-      assert.is_falsy(v)
-      assert.are.equal("interval is empty", err)
+    it("throws for invalid one-arg (m < 1, m ~= 0), like math.random", function()
+      local ok_math, _ = pcall(math.random, -1)
+      assert.is_falsy(ok_math, "math.random(-1) should error")
+      local ok_rnd, _ = pcall(system.rnd, -1)
+      assert.is_falsy(ok_rnd, "rnd(-1) should throw like math.random")
     end)
 
 
-    it("returns nil and error for wrong number of arguments", function()
-      local v, err = system.rnd(1, 2, 3)
-      assert.is_falsy(v)
-      assert.are.equal("wrong number of arguments", err)
+    it("throws for wrong number of arguments, like math.random", function()
+      local ok_math, _ = pcall(math.random, 1, 2, 3)
+      assert.is_falsy(ok_math, "math.random(1, 2, 3) should error")
+      local ok_rnd, _ = pcall(system.rnd, 1, 2, 3)
+      assert.is_falsy(ok_rnd, "rnd(1, 2, 3) should throw like math.random")
     end)
 
   end)