add tests

Author: tgymnich

test/output.jl

@@ -30,7 +30,7 @@
         # _, out = @grab_output begin
         #     Metal.@sync @metal kernel(x)
         # end
-        # @test out == "1.000000 1.000000\n" @broken=true
+        # @test out == "1.000000 1.000000\n"
     end
 
     @testset "@mtlprint" begin