diff --git a/src/components.jl b/src/components.jl
index 6495a7d..cebc742 100644
--- a/src/components.jl
+++ b/src/components.jl
@@ -81,6 +81,8 @@ function ComponentList(::Type{T}, d::Device) where {T<:AbstractComponent}
         SoapySDRDevice_listGPIOBanks(d, len)
     elseif T <: Register
         SoapySDRDevice_listRegisterInterfaces(d, len)
+    else
+        error("Unsupported component type: $T")
     end
     strlist = StringList(ptr, len[])
     ComponentList{T}(strlist)
diff --git a/src/device/stream.jl b/src/device/stream.jl
index aa40f8a..21db58f 100644
--- a/src/device/stream.jl
+++ b/src/device/stream.jl
@@ -199,7 +199,7 @@ function Base.read!(
             timeout_us,
         )
 
-        if typeof(flags) <: Ref
+        if flags isa Ref
             flags[] |= out_flags[]
         end
 
@@ -337,7 +337,7 @@ function Base.write(
             timeout_us,
         )
 
-        if typeof(flags) <: Ref
+        if flags isa Ref
             flags[] |= out_flags[]
         end
 
diff --git a/test/runtests.jl b/test/runtests.jl
index aa0cb29..9838ca9 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -286,6 +286,6 @@ SoapySDR.register_log_handler()
 
     isempty(VERSION.prerelease) && @testset "JET" begin
         using JET
-        JET.test_package(SoapySDR; target_modules=[SoapySDR])
+        JET.test_package(SoapySDR; target_defined_modules=true)
     end
 end