add missing test file

Author: Red-Portal

test/bijector.jl

@@ -0,0 +1,28 @@
+
+@testset "bijector.jl" begin
+    @testset "bijector" begin
+        @model function test()
+            m ~ Normal()
+            s ~ InverseGamma(3, 3)
+            return c ~ Dirichlet([1.0, 1.0])
+        end
+
+        m = test()
+        b = bijector(m)
+
+        # m ∈ ℝ, s ∈ ℝ+, c ∈ 2-simplex 
+        # check dimensionalities and ranges
+        @test b.length_in == 4
+        @test b.length_out == 3
+        @test b.ranges_in == [1:1, 2:2, 3:4]
+        @test b.ranges_out == [1:1, 2:2, 3:3]
+        @test b.ranges_out == [1:1, 2:2, 3:3]
+
+        # check support of mapped variables
+        binv = inverse(b)
+        zs = mapslices(binv, randn(b.length_out, 10000); dims=1)
+
+        @test all(zs[2, :] .≥ 0)
+        @test all(sum(zs[3:4, :]; dims=1) .≈ 1.0)
+    end
+end