Add tests for Stream.concat/1,2 and Enum.concat/1,2

Author: betawaffle

lib/elixir/test/elixir/enum_test.exs

@@ -56,10 +56,23 @@ defmodule EnumTest.List do
 
   test :concat_1 do
     assert Enum.concat([[1, [2], 3], [4], [5, 6]]) == [1, [2], 3, 4, 5, 6]
+    assert Enum.concat(1..3, []) == [1,2,3]
+
+    assert Enum.concat([[], []]) == []
+    assert Enum.concat([[]])     == []
+    assert Enum.concat([])       == []
+
+    assert Enum.concat([1..5, fn acc, _ -> acc end, [1]]) == [1,2,3,4,5,1]
   end
 
   test :concat_2 do
+    assert Enum.concat([], [1]) == [1]
     assert Enum.concat([1, [2], 3], [4, 5]) == [1, [2], 3, 4, 5]
+    assert Enum.concat(1..3, []) == [1,2,3]
+
+    assert Enum.concat([], []) == []
+
+    assert Enum.concat(fn acc, _ -> acc end, [1]) == [1]
   end
 
   test :fetch! do

lib/elixir/test/elixir/stream_test.exs

@@ -25,6 +25,37 @@ defmodule StreamTest do
     assert Enum.to_list(stream) == [3,5,7]
   end
 
+  test :concat_1 do
+    stream = Stream.concat([1..3, [], [4, 5, 6], [], 7..9])
+    assert is_function(stream)
+
+    assert Enum.to_list(stream) == [1,2,3,4,5,6,7,8,9]
+    assert Enum.take(stream, 5) == [1,2,3,4,5]
+
+    stream = Stream.concat([1..3, [4, 5, 6], Stream.cycle(7..100)])
+    assert is_function(stream)
+
+    assert Enum.take(stream, 13) == [1,2,3,4,5,6,7,8,9,10,11,12,13]
+  end
+
+  test :concat_2 do
+    stream = Stream.concat(1..3, 4..6)
+    assert is_function(stream)
+    assert Stream.cycle(stream) |> Enum.take(16) == [1,2,3,4,5,6,1,2,3,4,5,6,1,2,3,4]
+
+    stream = Stream.concat(1..3, [])
+    assert is_function(stream)
+    assert Stream.cycle(stream) |> Enum.take(5) == [1,2,3,1,2]
+
+    stream = Stream.concat(1..6, Stream.cycle(7..9))
+    assert is_function(stream)
+    assert Stream.drop(stream, 3) |> Enum.take(13) == [4,5,6,7,8,9,7,8,9,7,8,9,7]
+
+    stream = Stream.concat(Stream.cycle(1..3), Stream.cycle(4..6))
+    assert is_function(stream)
+    assert Enum.take(stream, 13) == [1,2,3,1,2,3,1,2,3,1,2,3,1]
+  end
+
   test :cycle do
     stream = Stream.cycle([1,2,3])
     assert is_function(stream)