From e540c24afca95a9f701847d13b09ba6cf1eadb4b Mon Sep 17 00:00:00 2001
From: Christian Guinard <28689358+christiangnrd@users.noreply.github.com>
Date: Mon, 27 Jul 2026 21:52:55 -0300
Subject: [PATCH] Add tests for host interface functions

---
 test/hostinterface.jl | 78 +++++++++++++++++++++++++++++++++++++++++++
 test/testsuite.jl     |  5 +++
 2 files changed, 83 insertions(+)
 create mode 100644 test/hostinterface.jl

diff --git a/test/hostinterface.jl b/test/hostinterface.jl
new file mode 100644
index 000000000..61eaa9823
--- /dev/null
+++ b/test/hostinterface.jl
@@ -0,0 +1,78 @@
+function hostinterface_testsuite(_backend, AT)
+    backend = _backend()
+
+    @testset "capability queries" begin
+        @test KernelAbstractions.supports_unified(backend) isa Bool
+        @test KernelAbstractions.supports_atomics(backend) isa Bool
+        @test KernelAbstractions.supports_float64(backend) isa Bool
+        @test KernelAbstractions.functional(backend) isa Union{Missing, Bool}
+    end
+
+    @testset "device management" begin
+        @test KernelAbstractions.device(backend) isa Int
+        @test KernelAbstractions.ndevices(backend) isa Int
+        @test KernelAbstractions.device!(backend, KernelAbstractions.device(backend)) === nothing
+        @test_throws ArgumentError KernelAbstractions.device!(backend, 0)
+        @test_throws ArgumentError KernelAbstractions.device!(backend, KernelAbstractions.ndevices(backend) + 1)
+    end
+
+    @testset "priority!" begin
+        @test KernelAbstractions.priority!(backend, :normal) === nothing
+        @test KernelAbstractions.priority!(backend, :high) === nothing
+        @test KernelAbstractions.priority!(backend, :low) === nothing
+        @test_throws ErrorException KernelAbstractions.priority!(backend, :bogus)
+    end
+
+    @testset "allocation" begin
+        A = KernelAbstractions.allocate(backend, Float32, 8)
+        @test A isa AT{Float32, 1}
+        @test size(A) == (8,)
+
+        Z = KernelAbstractions.zeros(backend, Float32, 4, 4)
+        @test all(iszero, Array(Z))
+
+        O = KernelAbstractions.ones(backend, Float32, 4, 4)
+        @test all(isone, Array(O))
+
+        if KernelAbstractions.supports_unified(backend)
+            U = KernelAbstractions.allocate(backend, Float32, 4; unified = true)
+            @test U isa AbstractArray{Float32}
+        else
+            @test_throws ArgumentError KernelAbstractions.allocate(backend, Float32, 4; unified = true)
+        end
+    end
+
+    @testset "get_backend" begin
+        A = KernelAbstractions.allocate(backend, Float32, 4)
+        @test KernelAbstractions.get_backend(A) isa Backend
+    end
+
+    @testset "pagelock!" begin
+        A = Vector{Float32}(undef, 4)
+        @test KernelAbstractions.pagelock!(backend, A) isa Union{Missing, Nothing}
+    end
+
+
+    @testset "KernelInterface host functions" begin
+        @test KI.max_work_group_size(backend) isa Int
+        @test KI.multiprocessor_count(backend) isa Int
+        @test KI.sub_group_size(backend) isa Int
+        @test KI.shfl_down_types(backend) isa Vector{DataType}
+
+        function ki_hostinterface_kernel(x)
+            i = KI.get_global_id().x
+            if i <= length(x)
+                @inbounds x[i] = 1
+            end
+            return
+        end
+
+        x = AT(zeros(Float32, 4))
+        kernel = KI.@kernel _backend() launch = false ki_hostinterface_kernel(x)
+        @test kernel isa KI.Kernel
+        @test KI.kernel_max_work_group_size(kernel) isa Int
+        @test KI.kernel_max_work_group_size(kernel; max_work_items = 1) == 1
+    end
+
+    return nothing
+end
diff --git a/test/testsuite.jl b/test/testsuite.jl
index 69fc89f19..ab2dd921f 100644
--- a/test/testsuite.jl
+++ b/test/testsuite.jl
@@ -28,6 +28,7 @@ end
 
 include("test.jl")
 include("interface.jl")
+include("hostinterface.jl")
 include("localmem.jl")
 include("private.jl")
 include("unroll.jl")
@@ -54,6 +55,10 @@ function testsuite(backend, backend_str, backend_mod, AT, DAT; skip_tests = Set{
         interface_testsuite(backend, AT)
     end
 
+    @conditional_testset "HostInterface" skip_tests begin
+        hostinterface_testsuite(backend, AT)
+    end
+
     @conditional_testset "Localmem" skip_tests begin
         localmem_testsuite(backend, AT)
     end