diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e06faac..b57725d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,7 +15,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.0'
+          - '1.3'
           - '1' # automatically expands to the latest stable 1.x release of Julia
           - 'nightly'
         os:
diff --git a/src/util.jl b/src/util.jl
index c7f45a8..998f50e 100644
--- a/src/util.jl
+++ b/src/util.jl
@@ -240,6 +240,11 @@ function _map_params(f, T, S)
 end
 
 _map_params(f, T::Type{Tuple{}},S::Type{Tuple{}}) = ()
+_map_params(f, T::Type{NamedTuple{(), Tuple{}}},S::Type{NamedTuple{(), Tuple{}}}) = ()
+
+if !hasmethod(Base.reduce_empty, Tuple{typeof(Base.add_sum), Union{}})
+    @noinline Base.reduce_empty(::typeof(Base.add_sum), ::Type{Union{}}) = throw(ArgumentError("reducing over an empty collection is not allowed"))
+end
 
 map_params(f, ::Type{T}, ::Type{S}) where {T,S} = f(T,S)
 @inline _tuple_type_head(::Type{T}) where {T<:Tuple} = Base.tuple_type_head(T)
diff --git a/test/test_misc.jl b/test/test_misc.jl
index e2d0537..bd0deba 100644
--- a/test/test_misc.jl
+++ b/test/test_misc.jl
@@ -28,7 +28,7 @@ end
 @testset  "printing" begin
     x = distribute(NDSparse([1], [1]), 1)
     @test repr(x) == """
-    1-d Distributed NDSparse with 1 values (Int64) in 1 chunks:
+    1-d Distributed NDSparse with 1 values ($Int) in 1 chunks:
     1 │
     ──┼──
     1 │ 1"""
diff --git a/test/test_readwrite.jl b/test/test_readwrite.jl
index 7ee942e..6b7d24f 100644
--- a/test/test_readwrite.jl
+++ b/test/test_readwrite.jl
@@ -24,7 +24,7 @@ end
 end
 
 
-path = joinpath(dirname(@__FILE__), "..","test", "sample")
+path = joinpath(dirname(pathof(JuliaDB)), "..","test", "sample")
 files = glob("*.csv", path)
 const spdata_dist = loadndsparse(files, type_detect_rows=4,
                               indexcols=1:2, usecache=false, chunks=2)
@@ -41,7 +41,7 @@ const spdata = loadndsparse(files;
                             distributed=false,
                             header_exists=true,
                             indexcols=1:2)
-files = glob("*.csv", "sample")
+files = glob("*.csv", path)
 shuffle_files = shuffle(files)
 const spdata_unordered = loadndsparse(shuffle_files;
                                       distributed=false,
diff --git a/test/test_table.jl b/test/test_table.jl
index 145b997..59844d9 100644
--- a/test/test_table.jl
+++ b/test/test_table.jl
@@ -12,16 +12,16 @@ import JuliaDB: pkeynames, pkeys, excludecols, select, transform
                     end), t, :x, select=:z) == table([1, 2], [6, 15], names=Symbol[:x, :y])
     @test groupreduce(:y => (+), t, :x, select=:z) == table([1, 2], [6, 15], names=Symbol[:x, :y])
     x = ndsparse(["a", "b"], [3, 4], chunks=2)
-    @test (keytype(x), eltype(x)) == (Tuple{String}, Int64)
+    @test (keytype(x), eltype(x)) == (Tuple{String}, Int)
     x = ndsparse((date = Date.(2014:2017),), [4:7;], chunks=2)
     @test x[Date("2015-01-01")] == 5
-    @test (keytype(x), eltype(x)) == (Tuple{Date}, Int64)
+    @test (keytype(x), eltype(x)) == (Tuple{Date}, Int)
     x = ndsparse((["a", "b"], [3, 4]), [5, 6], chunks=2)
-    @test (keytype(x), eltype(x)) == (Tuple{String,Int64}, Int64)
+    @test (keytype(x), eltype(x)) == (Tuple{String,Int}, Int)
     @test x["a", 3] == 5
     x = ndsparse((["a", "b"], [3, 4]), ([5, 6], [7.0, 8.0]), chunks=2)
     x = ndsparse((x = ["a", "a", "b"], y = [3, 4, 4]), (p = [5, 6, 7], q = [8.0, 9.0, 10.0]), chunks=2)
-    @test (keytype(x), eltype(x)) == (Tuple{String,Int64}, NamedTuple{(:p,:q),Tuple{Int64,Float64}})
+    @test (keytype(x), eltype(x)) == (Tuple{String,Int}, NamedTuple{(:p,:q),Tuple{Int,Float64}})
     @test x["a", :] == ndsparse((y = [3, 4],), Columns((p = [5, 6], q = [8.0, 9.0])))
     x = ndsparse([1, 2], [3, 4], chunks=2)
     @test pkeynames(x) == (1,)
@@ -223,7 +223,7 @@ import JuliaDB: pkeynames, pkeys, excludecols, select, transform
     @test isequal(convertmissing(t, DataValue), t2)
     @test isequal(convertmissing(t2, Missing), t)
 
-    @test typeof(column(dropmissing(t, :x), :x)) <: Dagger.DArray{Int64,1}
+    @test typeof(column(dropmissing(t, :x), :x)) <: Dagger.DArray{Int,1}
     t = table(["a", "b", "c"], [0.01, 0.05, 0.07], [2, 1, 0], names=[:n, :t, :x], chunks=2)
     @test filter((p->p.x / p.t < 100), t) == table(String["b", "c"], [0.05, 0.07], [1, 0], names=Symbol[:n, :t, :x])
     x = ndsparse((n = ["a", "b", "c"], t = [0.01, 0.05, 0.07]), [2, 1, 0], chunks=2)