fix bugs and add test

Project.toml

@@ -3,7 +3,7 @@ uuid = "7a57a42e-76ec-4ea3-a279-07e840d6d9cf"
 keywords = ["probablistic programming"]
 license = "MIT"
 desc = "Common interfaces for probabilistic programming"
-version = "0.10.0"
+version = "0.10.1"
 
 [deps]
 AbstractMCMC = "80f14c24-f653-4e6a-9b94-39d6b0f70001"

src/abstractprobprog.jl

@@ -128,5 +128,5 @@ end
 Draw a sample from the predictive distribution specified by `model` with its parameters fixed to `params`.
 """
 function StatsBase.predict(model::AbstractProbabilisticProgram, params)
-    return predict(Random.default_rng(), NamedTuple, model, params)
+    return StatsBase.predict(Random.default_rng(), model, params)
 end

test/abstractprobprog.jl

@@ -13,6 +13,12 @@ function Base.rand(rng::Random.AbstractRNG, ::Type{T}, model::RandModel) where {
     return nothing
 end
 
+struct PredModel <: AbstractProbabilisticProgram end
+
+function AbstractPPL.predict(rng::Random.AbstractRNG, model::PredModel, params)
+    return rng
+end
+
 @testset "AbstractProbabilisticProgram" begin
     @testset "rand defaults" begin
         model = RandModel(nothing, nothing)
@@ -34,4 +40,9 @@ end
             @test model.T === NamedTuple
         end
     end
+
+    @testset "predict defaults" begin
+        model = PredModel()
+        @test AbstractPPL.predict(model, nothing) == Random.default_rng()
+    end
 end