--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/SbpOperators/boundary_conditions/boundary_condition_test.jl	Sat Jan 11 10:19:47 2025 +0100
@@ -0,0 +1,39 @@
+using Test
+
+using Diffinitive.Grids
+using Diffinitive.RegionIndices
+using Diffinitive.SbpOperators
+
+@testset "BoundaryCondition" begin
+    grid_1d = equidistant_grid(0.0, 1.0, 11)
+    grid_2d = equidistant_grid((0.0, 0.0), (1.0,1.0), 11, 15)
+    grid_3d = equidistant_grid((0.0, 0.0, 0.0), (1.0,1.0, 1.0), 11, 15, 13)
+    (id_l,_) = boundary_identifiers(grid_1d)
+    (_,_,_,id_n) = boundary_identifiers(grid_2d)
+    (_,_,_,_,id_b,_) = boundary_identifiers(grid_3d)
+
+    g = 3.14
+    f(x,y,z) = x^2+y^2+z^2
+    @testset "Constructors" begin
+        @test DirichletCondition(g,id_l) isa DirichletCondition{Float64,LowerBoundary}
+        @test NeumannCondition(f,id_b) isa NeumannCondition{<:Function,CartesianBoundary{3,LowerBoundary}}
+    end
+
+    @testset "boundary" begin
+        @test boundary(DirichletCondition(g,id_l)) == id_l
+        @test boundary(NeumannCondition(f,id_b)) == id_b
+    end
+
+    @testset "boundary_data" begin
+        @test boundary_data(DirichletCondition(g,id_l)) == g
+        @test boundary_data(NeumannCondition(f,id_b)) == f
+    end
+
+    @testset "discretize_data" begin
+        @test fill(g) ≈ discretize_data(grid_1d,DirichletCondition(g,id_l))
+        @test g*ones(11,1) ≈ discretize_data(grid_2d,DirichletCondition(g,id_n))
+        X = repeat(0:1/10:1, inner = (1,15))
+        Y = repeat(0:1/14:1, outer = (1,11))
+        @test map((x,y)->f(x,y,0), X,Y') ≈ discretize_data(grid_3d,NeumannCondition(f,id_b))
+    end
+end