Add tests for StreamSampler functionality (#136)

Author: ameligrana

test/runtests.jl

@@ -16,8 +16,10 @@ using StreamSampling
     include("unweighted_sampling_multi_tests.jl")
     include("weighted_sampling_single_tests.jl")
     include("weighted_sampling_multi_tests.jl")
+    include("stream_sampling_tests.jl")
     include("sequential_sampling_tests.jl")
     include("merge_tests.jl")
     include("empty_tests.jl")
     include("benchmark_tests.jl")
 end
+

test/stream_sampling_tests.jl

@@ -0,0 +1,77 @@
+@testset "StreamSampler tests" begin
+    rng = StableRNG(45)
+    N = 10
+    n = 3
+    reps = 100000
+
+    for alg in (AlgD(), AlgHiddenShuffle())
+        dict_res = Dict{Vector{Int}, Int}()
+        for _ in 1:reps
+            s = StreamSampler{Int}(rng, 1:N, n, N, alg)
+            out = collect(s)
+            dict_res[out] = get(dict_res, out, 0) + 1
+        end
+        
+        valid_triples = 120
+        count_est = Int[]
+        for i in 1:N, j in i+1:N, k in j+1:N
+            push!(count_est, get(dict_res, [i, j, k], 0))
+        end
+        
+        chisq_test = ChisqTest(count_est, fill(1/valid_triples, valid_triples))
+        @test pvalue(chisq_test) > 0.05
+    end
+
+    dict_res = Dict{Vector{Int}, Int}()
+    for _ in 1:reps
+        s = StreamSampler{Int}(rng, 1:N, n, N, AlgORDSWR())
+        out = collect(s)
+        dict_res[out] = get(dict_res, out, 0) + 1
+    end
+    
+    count_est = Int[]
+    ps_exact = Float64[]
+    for i in 1:N, j in i:N, k in j:N
+        push!(count_est, get(dict_res, [i, j, k], 0))
+        if i == j == k
+            push!(ps_exact, 1/(N^3))
+        elseif i == j || j == k
+            push!(ps_exact, 3/(N^3))
+        else
+            push!(ps_exact, 6/(N^3))
+        end
+    end
+    
+    chisq_test = ChisqTest(count_est, ps_exact)
+    @test pvalue(chisq_test) > 0.05
+
+    weights = [i <= 5 ? 1.0 : 2.0 for i in 1:N]
+    W = sum(weights)
+    wfunc(i) = weights[i]
+    
+    dict_res = Dict{Vector{Int}, Int}()
+    for _ in 1:reps
+        s = StreamSampler{Int}(rng, 1:N, wfunc, n, W, AlgORDWSWR())
+        out = collect(s)
+        dict_res[out] = get(dict_res, out, 0) + 1
+    end
+    
+    count_est = Int[]
+    ps_exact = Float64[]
+    for i in 1:N, j in i:N, k in j:N
+        push!(count_est, get(dict_res, [i, j, k], 0))
+        wi, wj, wk = weights[i], weights[j], weights[k]
+        if i == j == k
+            push!(ps_exact, (wi^3) / (W^3))
+        elseif i == j
+            push!(ps_exact, 3 * (wi^2 * wk) / (W^3))
+        elseif j == k
+            push!(ps_exact, 3 * (wi * wj^2) / (W^3))
+        else
+            push!(ps_exact, 6 * (wi * wj * wk) / (W^3))
+        end
+    end
+    
+    chisq_test = ChisqTest(count_est, ps_exact)
+    @test pvalue(chisq_test) > 0.05
+end