diff --git a/test/WeakKeyIdDict-test.jl b/test/WeakKeyIdDict-test.jl
index a243db78a4..b79ba6adc8 100644
--- a/test/WeakKeyIdDict-test.jl
+++ b/test/WeakKeyIdDict-test.jl
@@ -13,21 +13,41 @@
     @test WeakKeyIdDict(dd) == wkd
     @test convert(WeakKeyIdDict{Any, Any}, dd) == wkd
     @test isa(WeakKeyIdDict(dd), WeakKeyIdDict{Any,Any})
+
+    # test many constructors without type parameters specified
     @test WeakKeyIdDict(A=>2, B=>3, C=>4) == wkd
-    @test isa(WeakKeyIdDict(A=>2, B=>3, C=>4), WeakKeyIdDict{Array{Int,1},Int})
+    @test isa(WeakKeyIdDict(A=>2, B=>3, C=>4), WeakKeyIdDict{Vector{Int},Int})
     @test WeakKeyIdDict(a=>i+1 for (i,a) in enumerate([A,B,C]) ) == wkd
     @test WeakKeyIdDict([(A,2), (B,3), (C,4)]) == wkd
     @test WeakKeyIdDict(Pair(A,2), Pair(B,3), Pair(C,4)) == wkd
+
+    # test many constructors with type parameters specified
+    @test WeakKeyIdDict{Vector{Int},Int}(A=>2, B=>3, C=>4) == wkd
+    @test isa(WeakKeyIdDict{Vector{Int},Int}(A=>2, B=>3, C=>4), WeakKeyIdDict{Vector{Int},Int})
+    @test WeakKeyIdDict{Vector{Int},Int}(a=>i+1 for (i,a) in enumerate([A,B,C]) ) == wkd
+    @test WeakKeyIdDict{Vector{Int},Int}([(A,2), (B,3), (C,4)]) == wkd
+    @test WeakKeyIdDict{Vector{Int},Int}(Pair(A,2), Pair(B,3), Pair(C,4)) == wkd
+
+    # test more constructors with mixed types
+    @test isa(WeakKeyIdDict(A=>2, B=>3, C=>"4"), WeakKeyIdDict{Vector{Int},Any})
+    @test isa(WeakKeyIdDict(A=>2, B=>3, "C"=>4), WeakKeyIdDict{Any,Int})
+    @test isa(WeakKeyIdDict(A=>2, B=>3, "C"=>"4"), WeakKeyIdDict{Any,Any})
+
     @test copy(wkd) == wkd
 
     @test length(wkd) == 3
     @test !isempty(wkd)
+    @test haskey(wkd, C)
+    @test getkey(wkd, C, 123) === C
     res = pop!(wkd, C)
     @test res == 4
     @test C ∉ keys(wkd)
     @test 4 ∉ values(wkd)
+    @test !haskey(wkd, C)
     @test length(wkd) == 2
     @test !isempty(wkd)
+    @test 47 == pop!(wkd, C, 47)
+    @test getkey(wkd, C, 123) == 123
     wkd = filter!( p -> p.first != B, wkd)
     @test B ∉ keys(wkd)
     @test 3 ∉ values(wkd)
@@ -35,18 +55,59 @@
     @test WeakKeyIdDict(Pair(A, 2)) == wkd
     @test !isempty(wkd)
 
+    wkd[A] = 42
+    @test wkd[A] == 42
+
+    wkd = WeakKeyIdDict(A=>2, B=>3, C=>4)
+    map!(x -> x + 1, values(wkd))
+    @test WeakKeyIdDict(A=>3, B=>4, C=>5) == wkd
+
+    wkd = WeakKeyIdDict(A=>2, B=>3, C=>4)
+    @test delete!(wkd, A) == WeakKeyIdDict(B=>3, C=>4)
+    @test delete!(wkd, A) == WeakKeyIdDict(B=>3, C=>4)  # deleting the same key twice works
+    @test delete!(wkd, C) == WeakKeyIdDict(B=>3)
+    @test delete!(wkd, B) == WeakKeyIdDict()
+    # adding stuff back is OK
+    wkd[A] = 2
+    wkd[B] = 3
+    wkd[C] = 4
+    @test wkd == WeakKeyIdDict(A=>2, B=>3, C=>4)
+
+    wkd = WeakKeyIdDict(A=>2)
+    @test get(wkd, A, 17) == 2
+    @test get!(wkd, A, 17) == 2
+    @test get(wkd, B, 17) == 17
+    @test length(wkd) == 1
+    @test get!(wkd, B, 17) == 17
+    @test length(wkd) == 2
+
+    wkd = WeakKeyIdDict(A=>2)
+    @test get(() -> 23, wkd, A) == 2
+    @test get!(() -> 23, wkd, A) == 2
+    @test get(() -> 23, wkd, B) == 23
+    @test length(wkd) == 1
+    @test get!(() -> 23, wkd, B) == 23
+    @test length(wkd) == 2
+
     wkd = empty!(wkd)
     @test wkd == empty(wkd)
+    @test wkd == empty(wkd)
     @test typeof(wkd) == typeof(empty(wkd))
     @test length(wkd) == 0
     @test isempty(wkd)
     @test isa(wkd, WeakKeyIdDict)
+    @test WeakKeyIdDict() == WeakKeyIdDict(())
 
     @test_throws ArgumentError WeakKeyIdDict([1, 2, 3])
 
     # WeakKeyIdDict does not convert keys
     @test_throws ArgumentError WeakKeyIdDict{Int,Any}(5.0=>1)
 
+    # iterator
+    wkd = WeakKeyIdDict(A=>2, B=>3, C=>4)
+    @test Set(collect(wkd)) == Set([A=>2, B=>3, C=>4])
+    @test 2+3+4 == sum(v for (k,v) in wkd)
+
     # WeakKeyIdDict hashes with object-id
     AA = copy(A)
     GC.@preserve A AA begin
@@ -66,4 +127,31 @@
     d26939 = WeakKeyIdDict()
     d26939[big"1.0" + 1.1] = 1
     GC.gc() # make sure this doesn't segfault
+
+end
+
+# The following tests involve the garbage collector and
+# don't work if they are inside a @testset
+wkd = WeakKeyIdDict([42]=>2, [43]=>3, [44]=>4)
+for k in keys(wkd)
+  delete!(wkd, k)
 end
+@test isempty(wkd)
+GC.gc()  # try to get it to evict some weak references
+@test isempty(wkd)
+
+# verify that garbage collection takes care of our weak references
+A = [1]
+wkd = WeakKeyIdDict(A => 1)
+let tmp = [ 42 ]
+  @test length(wkd) == 1
+  wkd[tmp] = 2
+  @test length(wkd) == 2
+end
+# at this point there is no strong reference left to the vector [42]
+# previously reachable via tmp
+GC.gc(true)
+
+@test length(wkd) == 1
+@test length(keys(wkd)) == 1
+@test WeakKeyIdDict(A => 1) == wkd