diff --git a/src/testdir/test_lambda.vim b/src/testdir/test_lambda.vim
index cbd4add..02face8 100644
--- a/src/testdir/test_lambda.vim
+++ b/src/testdir/test_lambda.vim
@@ -21,7 +21,7 @@
   let s:timer_id = 0
   function! s:Foo()
     "let n = 0
-    let s:timer_id = timer_start(50, {-> execute("let s:n += 1 | echo s:n")}, {"repeat": -1})
+    let s:timer_id = timer_start(50, {-> execute("let s:n += 1 | echo s:n", "")}, {"repeat": -1})
   endfunction
 
   call s:Foo()
@@ -51,3 +51,161 @@
   let x = {'>' : 'foo'}
   call assert_equal('foo', x['>'])
 endfunc
+
+function! Test_lambda_capture_by_reference()
+  let v = 1
+  let l:F = {x -> x + v}
+  let v = 2
+  call assert_equal(12, l:F(10))
+endfunction
+
+function! Test_lambda_side_effect()
+  function! s:update_and_return(arr)
+    let a:arr[1] = 5
+    return a:arr
+  endfunction
+
+  function! s:foo(arr)
+    return {-> s:update_and_return(a:arr)}
+  endfunction
+
+  let arr = [3,2,1]
+  call assert_equal([3, 5, 1], s:foo(arr)())
+endfunction
+
+function! Test_lambda_refer_local_variable_from_other_scope()
+  function! s:foo(X)
+    return a:X() " refer l:x in s:bar()
+  endfunction
+
+  function! s:bar()
+    let x = 123
+    return s:foo({-> x})
+  endfunction
+
+  call assert_equal(123, s:bar())
+endfunction
+
+function! Test_lambda_do_not_share_local_variable()
+  function! s:define_funcs()
+    let l:One = {-> split(execute("let a = 'abc' | echo a"))[0]}
+    let l:Two = {-> exists("a") ? a : "no"}
+    return [l:One, l:Two]
+  endfunction
+
+  let l:F = s:define_funcs()
+
+  call assert_equal('no', l:F[1]())
+  call assert_equal('abc', l:F[0]())
+  call assert_equal('no', l:F[1]())
+endfunction
+
+function! Test_lambda_closure()
+  function! s:foo()
+    let x = 0
+    return {-> [execute("let x += 1"), x][-1]}
+  endfunction
+
+  let l:F = s:foo()
+  call test_garbagecollect_now()
+  call assert_equal(1, l:F())
+  call assert_equal(2, l:F())
+  call assert_equal(3, l:F())
+  call assert_equal(4, l:F())
+endfunction
+
+function! Test_lambda_with_a_var()
+  function! s:foo()
+    let x = 2
+    return {... -> a:000 + [x]}
+  endfunction
+  function! s:bar()
+    return s:foo()(1)
+  endfunction
+
+  call assert_equal([1, 2], s:bar())
+endfunction
+
+function! Test_lambda_call_lambda_from_lambda()
+  function! s:foo(x)
+    let l:F1 = {-> {-> a:x}}
+    return {-> l:F1()}
+  endfunction
+
+  let l:F = s:foo(1)
+  call assert_equal(1, l:F()())
+endfunction
+
+function! Test_lambda_delfunc()
+  function! s:gen()
+    let pl = l:
+    let l:Foo = {-> get(pl, "Foo", get(pl, "Bar", {-> 0}))}
+    let l:Bar = l:Foo
+    delfunction l:Foo
+    return l:Bar
+  endfunction
+
+  let l:F = s:gen()
+  call assert_fails(':call l:F()', 'E117:')
+endfunction
+
+function! Test_lambda_scope()
+  function! s:NewCounter()
+    let c = 0
+    return {-> [execute('let c += 1'), c][-1]}
+  endfunction
+
+  function! s:NewCounter2()
+    return {-> [execute('let c += 100'), c][-1]}
+  endfunction
+
+  let l:C = s:NewCounter()
+  let l:D = s:NewCounter2()
+
+  call assert_equal(1, l:C())
+  call assert_fails(':call l:D()', 'E15:') " E121: then E15:
+  call assert_equal(2, l:C())
+endfunction
+
+function! Test_lambda_share_scope()
+  function! s:New()
+    let c = 0
+    let l:Inc0 = {-> [execute('let c += 1'), c][-1]}
+    let l:Dec0 = {-> [execute('let c -= 1'), c][-1]}
+    return [l:Inc0, l:Dec0]
+  endfunction
+
+  let [l:Inc, l:Dec] = s:New()
+
+  call assert_equal(1, l:Inc())
+  call assert_equal(2, l:Inc())
+  call assert_equal(1, l:Dec())
+endfunction
+
+function! Test_lambda_circular_reference()
+  function! s:Foo()
+    let d = {}
+    let d.f = {-> d}
+    return d.f
+  endfunction
+
+  call s:Foo()
+  call test_garbagecollect_now()
+  let i = 0 | while i < 10000 | call s:Foo() | let i+= 1 | endwhile
+  call test_garbagecollect_now()
+endfunction
+
+function! Test_lambda_combination()
+  call assert_equal(2, {x -> {x -> x}}(1)(2))
+  call assert_equal(10, {y -> {x -> x(y)(10)}({y -> y})}({z -> z}))
+  call assert_equal(5.0, {x -> {y -> x / y}}(10)(2.0))
+  call assert_equal(6, {x -> {y -> {z -> x + y + z}}}(1)(2)(3))
+
+  call assert_equal(6, {x -> {f -> f(x)}}(3)({x -> x * 2}))
+  call assert_equal(6, {f -> {x -> f(x)}}({x -> x * 2})(3))
+
+  " Z combinator
+  let Z = {f -> {x -> f({y -> x(x)(y)})}({x -> f({y -> x(x)(y)})})}
+  let Fact = {f -> {x -> x == 0 ? 1 : x * f(x - 1)}}
+  call assert_equal(120, Z(Fact)(5))
+endfunction