--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/Grids/zero_dim_grid_test.jl	Tue Feb 10 22:41:19 2026 +0100
@@ -0,0 +1,48 @@
+using Test
+using Diffinitive.Grids
+using StaticArrays
+
+@testset "ZeroDimGrid" begin
+    @test ZeroDimGrid(1) isa ZeroDimGrid{Int}
+    @test ZeroDimGrid([1,2,3]) isa ZeroDimGrid{Vector{Int}}
+    @test ZeroDimGrid(@SVector[1.0,2.0]) isa ZeroDimGrid{SVector{2,Float64}}
+
+    @testset "Indexing Interface" begin
+        g = ZeroDimGrid(@SVector[1,2])
+
+        @test g[] == [1,2]
+        @test eachindex(g) == CartesianIndices(())
+    end
+
+    @testset "Iterator interface" begin
+        g = ZeroDimGrid(@SVector[1,2])
+
+        @test Base.IteratorSize(g) == Base.HasShape{0}()
+        @test eltype(g) == SVector{2,Int}
+        @test length(g) == 1
+        @test size(g) == ()
+        @test collect(g) == fill(@SVector[1,2])
+    end
+
+    @testset "refine" begin
+        @test refine(ZeroDimGrid(@SVector[1.0,2.0]),1) == ZeroDimGrid(@SVector[1.0,2.0])
+        @test refine(ZeroDimGrid(@SVector[1.0,2.0]),2) == ZeroDimGrid(@SVector[1.0,2.0])
+    end
+
+    @testset "coarsen" begin
+        @test coarsen(ZeroDimGrid(@SVector[1.0,2.0]),1) == ZeroDimGrid(@SVector[1.0,2.0])
+        @test coarsen(ZeroDimGrid(@SVector[1.0,2.0]),2) == ZeroDimGrid(@SVector[1.0,2.0])
+    end
+
+    @testset "boundary_identifiers" begin
+        @test boundary_identifiers(ZeroDimGrid(@SVector[1.0,2.0])) == ()
+    end
+
+    @testset "boundary_grid" begin
+        @test_throws ArgumentError("ZeroDimGrid has no boundaries") boundary_grid(ZeroDimGrid(@SVector[1.0,2.0]), :bid)
+    end
+
+    @testset "boundary_indices" begin
+        @test_throws ArgumentError("ZeroDimGrid has no boundaries") boundary_indices(ZeroDimGrid(@SVector[1.0,2.0]), :bid)
+    end
+end