added tests for yield, yield from, yield return and yield in if statements

Author: alubbe

test/generators.coffee

@@ -7,23 +7,18 @@ test "generator as argument", ->
   ok -> yield 0
 
 test "generator definition", ->
-  x = ->
+  x = do ->
     yield 0
     yield 1
     yield 2
-  y = x()
-  z = y.next()
-  eq z.value, 0
-  eq z.done, false
-  z = y.next()
-  eq z.value, 1
-  eq z.done, false
-  z = y.next()
-  eq z.value, 2
-  eq z.done, false
-  z = y.next()
-  eq z.value, undefined
-  eq z.done, true
+  y = x.next()
+  ok y.value is 0 and y.done is false
+  y = x.next()
+  ok y.value is 1 and y.done is false
+  y = x.next()
+  ok y.value is 2 and y.done is false
+  y = x.next()
+  ok y.value is undefined and y.done is true
 
 test "bound generator", ->
   obj =
@@ -42,3 +37,45 @@ test "bound generator", ->
   eq obj, obj.bound().next().value
   ok obj isnt obj.unbound().next().value
   eq obj, obj.nested().next().value.next().value.next().value
+
+test "error if `yield` occurs outside of a function", ->
+  throws -> CoffeeScript.compile 'yield 1'
+
+test "error if `yield from` occurs outside of a function", ->
+  throws -> CoffeeScript.compile 'yield from 1'
+
+test "`yield from` support", ->
+  x = do ->
+    yield from do ->
+      yield i for i in [3..4]
+
+  y = x.next()
+  ok y.value is 3 and y.done is false
+
+  y = x.next 1
+  ok y.value is 4 and y.done is false
+
+  y = x.next 2
+  arrayEq y.value, [1, 2]
+  ok y.done is true
+
+test "empty generator", ->
+  x = do -> yield return
+
+  y = x.next()
+  ok y.value is undefined and y.done is true 
+
+test "`yield` by itself not at the end of a function errors", ->
+  throws -> CoffeeScript.compile 'x = -> yield; return'
+
+test "`yield from` at the end of a function errors", ->
+  throws -> CoffeeScript.compile 'x = -> x = 1; yield from'
+
+test "yield in if statements", ->
+  x = do -> if 1 is yield 2 then 3 else 4
+
+  y = x.next()
+  ok y.value is 2 and y.done is false
+
+  y = x.next 1
+  ok y.value is 3 and y.done is true