diff --git a/test/runtests.jl b/test/runtests.jl
index ad8d3e33..f32cadaa 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -28,15 +28,30 @@ using Test, PerformanceTestTools
 end
 
 module VSCodeServer
+    using TypedSyntax
+
     struct InlineDisplay
         is_repl::Bool
     end
     const INLAY_HINTS_ENABLED = Ref(true)
     const DIAGNOSTICS_ENABLED = Ref(true)
 
+    inlay_hints = []
+    diagnostics = []
+
     function Base.display(d::InlineDisplay, x)
+        if x isa Dict{String, Vector{TypedSyntax.InlayHint}}
+            push!(inlay_hints, x)
+        elseif eltype(x) == TypedSyntax.Diagnostic
+            push!(diagnostics, x)
+        end
         return nothing
     end
+
+    function reset_test_containers()
+        empty!(inlay_hints)
+        empty!(diagnostics)
+    end
 end
 module TestVSCodeExt # stops modules defined in test files from overwriting stuff from previous test
 using Test, PerformanceTestTools, ..VSCodeServer
diff --git a/test/test_codeview_vscode.jl b/test/test_codeview_vscode.jl
index c69fb3dd..b6eeb309 100644
--- a/test/test_codeview_vscode.jl
+++ b/test/test_codeview_vscode.jl
@@ -1,22 +1,279 @@
 module test_codeview_vscode
-    using Cthulhu, Test, Revise, REPL, ..VSCodeServer
-    
-    @testset "VSCode descend test" begin
-        if !isdefined(@__MODULE__, :fake_terminal)
-            @eval (@__MODULE__) begin
-                includet(@__MODULE__, normpath(@__DIR__, "FakeTerminals.jl"))   # FIXME change to include
-                using .FakeTerminals
+
+using Cthulhu, Test, Revise, REPL, ..VSCodeServer, TypedSyntax
+import TypedSyntax: InlayHintKinds
+
+include("test_vscode_example_functions.jl")
+
+@testset "VSCode descend test" begin
+    if !isdefined(@__MODULE__, :fake_terminal)
+        @eval (@__MODULE__) begin
+            includet(@__MODULE__, normpath(@__DIR__, "FakeTerminals.jl"))   # FIXME change to include
+            using .FakeTerminals
+        end
+    end
+
+    function equal_upto_ordering(x, y)
+        if length(x) != length(y) 
+            return false
+        end
+
+        while length(x) > 0
+            element = pop!(x)
+            found_idx = findfirst(x->x==element, y)
+            if !isnothing(found_idx)
+                deleteat!(y, found_idx)
+            else
+                return false
+            end
+        end
+        return true
+    end
+
+    for inlay_types_vscode in (true, false), diagnostics_vscode in (true, false), iswarn in (true, false), hide_type_stable in (true, false)
+        @testset "fib inlay_types_vscode=$inlay_types_vscode, diagnostics_vscode=$diagnostics_vscode, iswarn=$iswarn, hide_type_stable=$hide_type_stable" begin
+            VSCodeServer.reset_test_containers()
+
+            fake_terminal() do term, in, out, _
+                t = @async begin
+                    @test_nowarn descend(fib, (Int64,); terminal=term, iswarn, hide_type_stable, inlay_types_vscode, diagnostics_vscode)
+                end
+                write(in, 'q')
+                wait(t)
+            end
+            
+            if inlay_types_vscode
+                @test length(VSCodeServer.inlay_hints) == 2
+                @test isempty(VSCodeServer.inlay_hints[2])
+            else
+                @test length(VSCodeServer.inlay_hints) == 1
+                @test isempty(VSCodeServer.inlay_hints[1])
+            end
+
+            if diagnostics_vscode
+                @test length(VSCodeServer.diagnostics) == 2
+                @test isempty(VSCodeServer.diagnostics[2])
+                if !iswarn
+                    @test isempty(VSCodeServer.diagnostics[1])
+                end
+            end
+
+            if !hide_type_stable && inlay_types_vscode
+                @test equal_upto_ordering(first(values(VSCodeServer.inlay_hints[1])), [
+                    TypedSyntax.InlayHint(1, 14, "::Int64", 1)
+                    TypedSyntax.InlayHint(1, 15, "::Int64", 1)
+                    TypedSyntax.InlayHint(3, 11, "(", 1)
+                    TypedSyntax.InlayHint(3, 15, "(", 1)
+                    TypedSyntax.InlayHint(3, 16, "::Int64", 1)
+                    TypedSyntax.InlayHint(3, 20, ")::Int64", 1)
+                    TypedSyntax.InlayHint(3, 21, "::Int64", 1)
+                    TypedSyntax.InlayHint(3, 28, "(", 1)
+                    TypedSyntax.InlayHint(3, 29, "::Int64", 1)
+                    TypedSyntax.InlayHint(3, 33, ")::Int64", 1)
+                    TypedSyntax.InlayHint(3, 34, "::Int64", 1)
+                    TypedSyntax.InlayHint(3, 34, ")::Int64", 1)
+                ])
+            elseif hide_type_stable && inlay_types_vscode
+                @test isempty(VSCodeServer.inlay_hints[1])
+            end
+        end
+    end
+
+    for inlay_types_vscode in (true, false), diagnostics_vscode in (true, false), iswarn in (true, false), hide_type_stable in (true, false)
+        @testset "fVSCode inlay_types_vscode=$inlay_types_vscode, diagnostics_vscode=$diagnostics_vscode, iswarn=$iswarn, hide_type_stable=$hide_type_stable" begin
+            VSCodeServer.reset_test_containers()
+
+            fake_terminal() do term, in, out, _
+                t = @async begin
+                    @test_nowarn descend(fVSCode, (Int64,); terminal=term, iswarn, hide_type_stable, inlay_types_vscode, diagnostics_vscode)
+                end
+                write(in, 'q')
+                wait(t)
+            end
+            
+            if inlay_types_vscode
+                @test length(VSCodeServer.inlay_hints) == 2
+                @test isempty(VSCodeServer.inlay_hints[2])
+            else
+                @test length(VSCodeServer.inlay_hints) == 1
+                @test isempty(VSCodeServer.inlay_hints[1])
+            end
+
+            if diagnostics_vscode
+                @test length(VSCodeServer.diagnostics) == 2
+                @test isempty(VSCodeServer.diagnostics[2])
+                if iswarn
+                    @test equal_upto_ordering(getproperty.(VSCodeServer.diagnostics[1], :line), [8, 11])
+                    @test getproperty.(VSCodeServer.diagnostics[1], :severity) == [TypedSyntax.DiagnosticKinds.Information, TypedSyntax.DiagnosticKinds.Information]
+                    @test getproperty.(VSCodeServer.diagnostics[1], :msg) == ["Unstable Type", "Unstable Type"]
+                else
+                    @test isempty(VSCodeServer.diagnostics[1])
+                end
+            end
+
+            if !hide_type_stable && inlay_types_vscode
+                if iswarn
+                    @test equal_upto_ordering(first(values(VSCodeServer.inlay_hints[1])), [
+                        TypedSyntax.InlayHint(7, 18, "::Int64", 1)
+                        TypedSyntax.InlayHint(7, 19, "::Union{Float64, Int64}", nothing)
+                        TypedSyntax.InlayHint(8, 5, "::Int64", 1)
+                        TypedSyntax.InlayHint(8, 8, "(", 1)
+                        TypedSyntax.InlayHint(8, 9, "::Int64", 1)
+                        TypedSyntax.InlayHint(8, 13, ")::Int64", 1)
+                        TypedSyntax.InlayHint(9, 5, "::Int64", 1)
+                        TypedSyntax.InlayHint(9, 8, "(", 1)
+                        TypedSyntax.InlayHint(9, 13, "::Int64", 1)
+                        TypedSyntax.InlayHint(9, 13, ")::Int64", 1)
+                        TypedSyntax.InlayHint(10, 11, "(", 1)
+                        TypedSyntax.InlayHint(10, 12, "::Int64", 1)
+                        TypedSyntax.InlayHint(10, 16, "(", 1)
+                        TypedSyntax.InlayHint(10, 17, "::Int64", 1)
+                        TypedSyntax.InlayHint(10, 21, ")::Bool", 1)
+                        TypedSyntax.InlayHint(10, 26, "::Int64", 1)
+                        TypedSyntax.InlayHint(10, 32, "::Float64", 1)
+                        TypedSyntax.InlayHint(10, 33, ")::Union{Float64, Int64}", nothing)
+                    ])
+
+                else
+                    @test equal_upto_ordering(first(values(VSCodeServer.inlay_hints[1])), [
+                        TypedSyntax.InlayHint(7, 18, "::Int64", 1)
+                        TypedSyntax.InlayHint(7, 19, "::Union{Float64, Int64}", 1)
+                        TypedSyntax.InlayHint(8, 5, "::Int64", 1)
+                        TypedSyntax.InlayHint(8, 8, "(", 1)
+                        TypedSyntax.InlayHint(8, 9, "::Int64", 1)
+                        TypedSyntax.InlayHint(8, 13, ")::Int64", 1)
+                        TypedSyntax.InlayHint(9, 5, "::Int64", 1)
+                        TypedSyntax.InlayHint(9, 8, "(", 1)
+                        TypedSyntax.InlayHint(9, 13, "::Int64", 1)
+                        TypedSyntax.InlayHint(9, 13, ")::Int64", 1)
+                        TypedSyntax.InlayHint(10, 11, "(", 1)
+                        TypedSyntax.InlayHint(10, 12, "::Int64", 1)
+                        TypedSyntax.InlayHint(10, 16, "(", 1)
+                        TypedSyntax.InlayHint(10, 17, "::Int64", 1)
+                        TypedSyntax.InlayHint(10, 21, ")::Bool", 1)
+                        TypedSyntax.InlayHint(10, 26, "::Int64", 1)
+                        TypedSyntax.InlayHint(10, 32, "::Float64", 1)
+                        TypedSyntax.InlayHint(10, 33, ")::Union{Float64, Int64}", 1)
+                    ])
+                end
+            elseif hide_type_stable && inlay_types_vscode
+                if iswarn
+                    @test equal_upto_ordering(first(values(VSCodeServer.inlay_hints[1])), [
+                        TypedSyntax.InlayHint(7, 19, "::Union{Float64, Int64}", nothing)
+                        TypedSyntax.InlayHint(10, 11, "(", 1)
+                        TypedSyntax.InlayHint(10, 33, ")::Union{Float64, Int64}", nothing)
+                    ])
+                else
+                    @test equal_upto_ordering(first(values(VSCodeServer.inlay_hints[1])), [
+                        TypedSyntax.InlayHint(7, 19, "::Union{Float64, Int64}", 1)
+                        TypedSyntax.InlayHint(10, 11, "(", 1)
+                        TypedSyntax.InlayHint(10, 33, ")::Union{Float64, Int64}", 1)
+                    ])                
+                end
             end
         end
+    end
+
+    for inlay_types_vscode in (true, false), diagnostics_vscode in (true, false), iswarn in (true, false), hide_type_stable in (true, false)
+        @testset "fibcall Float64 inlay_types_vscode=$inlay_types_vscode, diagnostics_vscode=$diagnostics_vscode, iswarn=$iswarn, hide_type_stable=$hide_type_stable" begin
+            VSCodeServer.reset_test_containers()
+
+            fake_terminal() do term, in, out, _
+                t = @async begin
+                    @test_nowarn descend(fibcall, (Float64,); terminal=term, iswarn, hide_type_stable, inlay_types_vscode, diagnostics_vscode)
+                end
+                write(in, 'q')
+                wait(t)
+            end
+            
+            if inlay_types_vscode
+                @test length(VSCodeServer.inlay_hints) == 2
+                @test isempty(VSCodeServer.inlay_hints[2])
+            else
+                @test length(VSCodeServer.inlay_hints) == 1
+                @test isempty(VSCodeServer.inlay_hints[1])
+            end
 
-        function fib(n)
-            if n <= 1 return 1 end
-            return fib(n - 1) + fib(n - 2)
+            if inlay_types_vscode || (diagnostics_vscode && iswarn)
+                @test length(VSCodeServer.diagnostics) == 2
+                @test isempty(VSCodeServer.diagnostics[2])
+                @test length(VSCodeServer.diagnostics[1]) == 1
+                @test VSCodeServer.diagnostics[1][1].severity == TypedSyntax.DiagnosticKinds.Information
+                @test VSCodeServer.diagnostics[1][1].line == 2
+                @test VSCodeServer.diagnostics[1][1].msg == "Cthulhu disabled: This function was called multiple times with different argument types"
+            end
+
+            if !hide_type_stable && inlay_types_vscode
+                @test equal_upto_ordering(first(values(VSCodeServer.inlay_hints[1])), [
+                    TypedSyntax.InlayHint(14, 18, "::Float64", 1)
+                    TypedSyntax.InlayHint(14, 19, "::Int64", 1)
+                    TypedSyntax.InlayHint(15, 13, "::Type{Int64}", 1)
+                    TypedSyntax.InlayHint(15, 15, "::Float64", 1)
+                    TypedSyntax.InlayHint(15, 16, "::Int64", 1)
+                    TypedSyntax.InlayHint(16, 9, "::Float64", 1)
+                    TypedSyntax.InlayHint(16, 10, "::Int64", 1)
+                ])
+            elseif hide_type_stable && inlay_types_vscode
+                @test isempty(VSCodeServer.inlay_hints[1])
+            end
         end
+    end
 
-        fake_terminal() do term, in, out, _
-            @async @test_nowarn descend(fib, (Int,); terminal=term)
-            write(in, 'q')
+    for inlay_types_vscode in (true, false), diagnostics_vscode in (true, false), iswarn in (true, false), hide_type_stable in (true, false)
+        @testset "fibcall Int64 inlay_types_vscode=$inlay_types_vscode, diagnostics_vscode=$diagnostics_vscode, iswarn=$iswarn, hide_type_stable=$hide_type_stable" begin
+            VSCodeServer.reset_test_containers()
+
+            fake_terminal() do term, in, out, _
+                t = @async begin
+                    @test_nowarn descend(fibcall, (Int64,); terminal=term, iswarn, hide_type_stable, inlay_types_vscode, diagnostics_vscode)
+                end
+                write(in, 'q')
+                wait(t)
+            end
+            
+            if inlay_types_vscode
+                @test length(VSCodeServer.inlay_hints) == 2
+                @test isempty(VSCodeServer.inlay_hints[2])
+            else
+                @test length(VSCodeServer.inlay_hints) == 1
+                @test isempty(VSCodeServer.inlay_hints[1])
+            end
+
+            if diagnostics_vscode
+                @test length(VSCodeServer.diagnostics) == 2
+                @test isempty(VSCodeServer.diagnostics[2])
+                if !iswarn
+                    @test isempty(VSCodeServer.diagnostics[1])
+                end
+            end
+
+            if !hide_type_stable && inlay_types_vscode
+                @test equal_upto_ordering(first(values(VSCodeServer.inlay_hints[1])), [
+                    TypedSyntax.InlayHint(14, 18, "::Int64", 1)
+                    TypedSyntax.InlayHint(14, 19, "::Int64", 1)
+                    TypedSyntax.InlayHint(15, 13, "::Type{Int64}", 1)
+                    TypedSyntax.InlayHint(15, 15, "::Int64", 1)
+                    TypedSyntax.InlayHint(15, 16, "::Int64", 1)
+                    TypedSyntax.InlayHint(16, 9, "::Int64", 1)
+                    TypedSyntax.InlayHint(16, 10, "::Int64", 1)
+                    TypedSyntax.InlayHint(1, 14, "::Int64", 1)
+                    TypedSyntax.InlayHint(1, 15, "::Int64", 1)
+                    TypedSyntax.InlayHint(3, 11, "(", 1)
+                    TypedSyntax.InlayHint(3, 15, "(", 1)
+                    TypedSyntax.InlayHint(3, 16, "::Int64", 1)
+                    TypedSyntax.InlayHint(3, 20, ")::Int64", 1)
+                    TypedSyntax.InlayHint(3, 21, "::Int64", 1)
+                    TypedSyntax.InlayHint(3, 28, "(", 1)
+                    TypedSyntax.InlayHint(3, 29, "::Int64", 1)
+                    TypedSyntax.InlayHint(3, 33, ")::Int64", 1)
+                    TypedSyntax.InlayHint(3, 34, "::Int64", 1)
+                    TypedSyntax.InlayHint(3, 34, ")::Int64", 1)
+                ])
+            elseif hide_type_stable && inlay_types_vscode
+                @test isempty(VSCodeServer.inlay_hints[1])
+            end
         end
     end
+end
+
 end
\ No newline at end of file
diff --git a/test/test_vscode_example_functions.jl b/test/test_vscode_example_functions.jl
new file mode 100644
index 00000000..8de22280
--- /dev/null
+++ b/test/test_vscode_example_functions.jl
@@ -0,0 +1,18 @@
+# exact location in file matters
+function fib(n)
+    if n <= 1 return 1 end
+    return fib(n - 1) + fib(n - 2)
+end
+
+# exact location in file matters
+function fVSCode(x)
+    z = x + 1
+    y = 2 * z
+    return y + (x > 0 ? -1 : 1.0)
+end
+
+# exact location in file matters
+function fibcall(n)
+    fib(Int64(n))
+    fib(n)
+end
\ No newline at end of file