diff --git a/base/intset.jl b/base/intset.jl
index c0811797a80e1..bdd4bb94cb702 100644
--- a/base/intset.jl
+++ b/base/intset.jl
@@ -119,7 +119,7 @@ end
 
 function symdiff!(s::IntSet, n::Integer)
     if n >= s.limit
-        lim = Int(n + dim(n,2))
+        lim = Int(n + div(n,2))
         sizehint!(s, lim)
     elseif n < 0
         throw(ArgumentError("IntSet elements cannot be negative"))
@@ -274,7 +274,7 @@ function ==(s1::IntSet, s2::IntSet)
             return false
         end
     end
-    filln = s1.fill1s ? UInt32(-1) : UInt32(0)
+    filln = s1.fill1s ? reinterpret(UInt32, Int32(-1)) : UInt32(0)
     if lim1 > lim2
         for i = lim2:lim1
             if s1.bits[i] != filln
diff --git a/test/choosetests.jl b/test/choosetests.jl
index d92501c8847f8..8df4f11355546 100644
--- a/test/choosetests.jl
+++ b/test/choosetests.jl
@@ -31,7 +31,8 @@ function choosetests(choices = [])
         "replutil", "sets", "test", "goto", "llvmcall", "grisu",
         "nullable", "meta", "profile", "libgit2", "docs", "markdown",
         "base64", "serialize", "functors", "misc",
-        "enums", "cmdlineargs", "i18n", "workspace", "libdl", "int"
+        "enums", "cmdlineargs", "i18n", "workspace", "libdl", "int",
+        "intset"
     ]
 
     if Base.USE_GPL_LIBS
diff --git a/test/intset.jl b/test/intset.jl
new file mode 100644
index 0000000000000..63fb2022049f1
--- /dev/null
+++ b/test/intset.jl
@@ -0,0 +1,165 @@
+# This file is a part of Julia. License is MIT: http://julialang.org/license
+
+# Test functionality of IntSet
+
+
+## IntSet
+
+# Construction, collect
+data_in = (1,5,100)
+s = IntSet(data_in)
+data_out = collect(s)
+@test all(map(d->in(d,data_out), data_in))
+@test length(data_out) == length(data_in)
+
+# eltype, similar
+@test is(eltype(IntSet()), Int64)
+@test isequal(similar(IntSet([1,2,3])), IntSet())
+
+# show
+@test sprint(show, IntSet()) == "IntSet([])"
+@test sprint(show, IntSet([1,2,3])) == "IntSet([1, 2, 3])"
+@test contains(sprint(show, complement(IntSet())), "...,")
+
+
+s = IntSet([0,1,10,20,200,300,1000,10000,10002])
+@test last(s) == 10002
+@test first(s) == 0
+@test length(s) == 9
+@test pop!(s) == 10002
+@test length(s) == 8
+@test shift!(s) == 0
+@test length(s) == 7
+@test !in(0,s)
+@test !in(10002,s)
+@test in(10000,s)
+@test_throws ArgumentError first(IntSet())
+@test_throws ArgumentError last(IntSet())
+t = copy(s)
+sizehint!(t, 20000) #check that hash does not depend on size of internal Array{UInt32, 1}
+@test hash(s) == hash(t)
+@test hash(complement(s)) == hash(complement(t))
+
+@test setdiff(IntSet([1, 2, 3, 4]), IntSet([2, 4, 5, 6])) == IntSet([1, 3])
+@test symdiff(IntSet([1, 2, 3, 4]), IntSet([2, 4, 5, 6])) == IntSet([1, 3, 5, 6])
+
+s2 = IntSet([1, 2, 3, 4])
+setdiff!(s2, IntSet([2, 4, 5, 6]))
+
+@test s2 == IntSet([1, 3])
+
+# == with last-bit set (groups.google.com/forum/#!topic/julia-users/vZNjiIEG_sY)
+s = IntSet(255)
+@test s == s
+
+# issue #7851
+@test_throws ArgumentError IntSet(-1)
+@test !(-1 in IntSet(0:10))
+
+# # issue #8570
+# This requires 2^29 bytes of storage, which is too much for a simple test
+# s = IntSet(2^32)
+# @test length(s) == 1
+# for b in s; b; end
+
+i = IntSet([1, 2, 3])
+j = complement(i)
+
+for n in (0, 4, 171)
+    @test n in j
+end
+
+@test j.limit == 256
+@test length(j) == typemax(Int) - 3
+push!(j, 257)
+@test length(j) == typemax(Int) - 3
+
+pop!(j, 171)
+@test !(171 in j)
+@test length(j) == typemax(Int) - 4
+@test complement(j) == IntSet([1, 2, 3, 171])
+
+union!(i, [1, 2])
+@test length(i) == 3
+union!(i, [3, 4, 5])
+@test length(i) == 5
+
+@test_throws KeyError pop!(i, 10)
+
+empty!(i)
+@test length(i) == 0
+
+@test_throws ArgumentError symdiff!(i, -3)
+@test symdiff!(i, 3) == IntSet([3])
+@test symdiff!(i, 257) == IntSet([3, 257])
+@test symdiff!(i, [3, 6]) == IntSet([6, 257])
+
+i = IntSet(1:6)
+@test symdiff!(i, IntSet([6, 513])) == IntSet([1:5; 513])
+@test length(symdiff!(i, complement(i))) == typemax(Int)
+
+i = IntSet([1, 2, 3])
+k = IntSet([4, 5])
+copy!(k, i)
+@test k == i
+@test !(k === i)
+
+union!(i, complement(i))
+copy!(k, i)
+@test k == i
+@test !(k === i)
+
+# unions
+l = union!(i, complement(i))
+@test length(l) == typemax(Int)
+
+i = IntSet([1, 2, 3])
+j = union(i)
+@test j == i
+@test !(j === i)
+
+j = IntSet([4, 5, 6])
+@test union(i, j) == IntSet(1:6)
+
+k = IntSet([7, 8, 9])
+@test union(i, j, k) == IntSet(1:9)
+
+
+## intersections
+i = IntSet([1, 2, 3])
+j = IntSet([4, 5, 6])
+
+@test intersect(i) == i
+@test !(intersect(i) === i)
+
+@test intersect(i, j) == IntSet([])
+push!(j, 257)
+@test intersect(i, j) == IntSet([])
+push!(j, 2, 3, 17)
+@test intersect(i, j) == IntSet([2, 3])
+
+k = complement(j)
+@test intersect(i, k) == IntSet([1])
+
+l = IntSet([1, 3])
+@test intersect(i, k, l) == IntSet([1])
+
+
+## equality
+i = IntSet([1, 2, 3])
+@test !(i == complement(i))
+j = IntSet([1, 2, 4])
+@test i != j
+
+push!(j, 257)
+pop!(j, 257)
+@test i != j
+@test j != i
+
+@test issubset(IntSet([1, 2, 4]), IntSet(1:10))
+@test issubset(IntSet([]), IntSet([]))
+@test IntSet([1, 2, 4]) < IntSet(1:10)
+@test !(IntSet([]) < IntSet([]))
+@test IntSet([1, 2, 4]) <= IntSet(1:10)
+@test IntSet([1, 2, 4]) <= IntSet([1, 2, 4])
+@test IntSet([]) <= IntSet([])
diff --git a/test/sets.jl b/test/sets.jl
index 0c23aa0febb28..8570042f7f98a 100644
--- a/test/sets.jl
+++ b/test/sets.jl
@@ -213,62 +213,3 @@ filter!(isodd, s)
 @test first(Set(2)) == 2
 
 # ########## end of set tests ##########
-
-## IntSet
-
-# Construction, collect
-data_in = (1,5,100)
-s = IntSet(data_in)
-data_out = collect(s)
-@test all(map(d->in(d,data_out), data_in))
-@test length(data_out) == length(data_in)
-
-# eltype, similar
-@test is(eltype(IntSet()), Int64)
-@test isequal(similar(IntSet([1,2,3])), IntSet())
-
-# show
-@test sprint(show, IntSet()) == "IntSet([])"
-@test sprint(show, IntSet([1,2,3])) == "IntSet([1, 2, 3])"
-@test contains(sprint(show, complement(IntSet())), "...,")
-
-
-s = IntSet([0,1,10,20,200,300,1000,10000,10002])
-@test last(s) == 10002
-@test first(s) == 0
-@test length(s) == 9
-@test pop!(s) == 10002
-@test length(s) == 8
-@test shift!(s) == 0
-@test length(s) == 7
-@test !in(0,s)
-@test !in(10002,s)
-@test in(10000,s)
-@test_throws ArgumentError first(IntSet())
-@test_throws ArgumentError last(IntSet())
-t = copy(s)
-sizehint!(t, 20000) #check that hash does not depend on size of internal Array{UInt32, 1}
-@test hash(s) == hash(t)
-@test hash(complement(s)) == hash(complement(t))
-
-@test setdiff(IntSet([1, 2, 3, 4]), IntSet([2, 4, 5, 6])) == IntSet([1, 3])
-@test symdiff(IntSet([1, 2, 3, 4]), IntSet([2, 4, 5, 6])) == IntSet([1, 3, 5, 6])
-
-s2 = IntSet([1, 2, 3, 4])
-setdiff!(s2, IntSet([2, 4, 5, 6]))
-
-@test s2 == IntSet([1, 3])
-
-# == with last-bit set (groups.google.com/forum/#!topic/julia-users/vZNjiIEG_sY)
-s = IntSet(255)
-@test s == s
-
-# issue #7851
-@test_throws ArgumentError IntSet(-1)
-@test !(-1 in IntSet(0:10))
-
-# # issue #8570
-# This requires 2^29 bytes of storage, which is too much for a simple test
-# s = IntSet(2^32)
-# @test length(s) == 1
-# for b in s; b; end