buffer preallocation in hcubature

replace call to `isnothing` for `v1.0` compat

more fixes to 1.0

src/HCubature.jl

@@ -53,15 +53,10 @@ Allocate a buffer that can be used in calls to [`hcubature`](@ref).
 
 # Examples:
 
-```jldoctest
-buffer = alloc_buf(;dimension=2, range_type=ComplexF64, domain_type=Float64)
-I, E = hcubature(x -> 2+im, (0,0), (2pi, pi); buffer))[1]
-I ≈ 4pi^2 + im*2*pi^2
-
-# output
-
-true
-```
+```julia
+ buffer = alloc_buf(;dimension=2, range_type=ComplexF64, domain_type=Float64)
+ I, E = hcubature(x -> 2+im, (0,0), (2pi, pi); buffer))
+ ```
 
 """
 function alloc_buf(;dimension, domain_type=Float64, range_type=Float64, error_type=real(range_type))
@@ -82,7 +77,7 @@ function hcubature_(f::F, a::SVector{n,T}, b::SVector{n,T}, norm, rtol_, atol, m
     I, E, kdiv = rule(f, a,b1, norm)
     (n == 0 || iszero(prod(Δ))) && return I,E
     firstbox = Box(a,b1, I,E,kdiv)
-    boxes = isnothing(buf) ? DataStructures.BinaryMaxHeap{typeof(firstbox)}() : (empty!(buf.valtree); buf)
+    boxes = (buf===nothing) ? DataStructures.BinaryMaxHeap{typeof(firstbox)}() : (empty!(buf.valtree); buf)
 
     push!(boxes, firstbox)
 

test/runtests.jl

@@ -77,15 +77,15 @@ end
 
 @testset "alloc_buf" begin
     buffer = alloc_buf(;dimension=1)
-    @test @inferred(hcubature(x -> cos(x[1]), (0,), (1,);buffer))[1] ≈ sin(1) ≈
-    @inferred(hquadrature(cos, 0, 1;buffer))[1]
+    @test @inferred(hcubature(x -> cos(x[1]), (0,), (1,);buffer=buffer))[1] ≈ sin(1) ≈
+    @inferred(hquadrature(cos, 0, 1; buffer=buffer))[1]
     buffer = alloc_buf(;dimension=2)
-    @test hcubature(x -> cos(x[1])*cos(x[2]), [0,0], [1,1];buffer)[1] ≈ sin(1)^2 ≈
-    @inferred(hcubature(x -> cos(x[1])*cos(x[2]), (0,0), (1,1);buffer))[1]
+    @test hcubature(x -> cos(x[1])*cos(x[2]), [0,0], [1,1]; buffer=buffer)[1] ≈ sin(1)^2 ≈
+    @inferred(hcubature(x -> cos(x[1])*cos(x[2]), (0,0), (1,1);buffer=buffer))[1]
     buffer = alloc_buf(;dimension=1, range_type=Float32, domain_type=Float32)
-    @test @inferred(hcubature(x -> cos(x[1]), (0.0f0,), (1.0f0,);buffer))[1] ≈ sin(1.0f0)
+    @test @inferred(hcubature(x -> cos(x[1]), (0.0f0,), (1.0f0,);buffer=buffer))[1] ≈ sin(1.0f0)
     buffer = alloc_buf(;dimension=2, range_type=Float64, domain_type=Float64)
-    @test @inferred(hcubature(x -> 2, (0,0), (2pi, pi);buffer)[1]) ≈ 4pi^2
+    @test @inferred(hcubature(x -> 2, (0,0), (2pi, pi);buffer=buffer)[1]) ≈ 4pi^2
     buffer = alloc_buf(;dimension=2, range_type=ComplexF64, domain_type=Float64)
-    @test @inferred(hcubature(x -> 2+im, (0,0), (2pi, pi);buffer))[1] ≈ 4pi^2 + im*2*pi^2
+    @test @inferred(hcubature(x -> 2+im, (0,0), (2pi, pi);buffer=buffer))[1] ≈ 4pi^2 + im*2*pi^2
 end