diff --git a/test/parser/position_test.exs b/test/parser/position_test.exs
index 855ebcd..c54be43 100644
--- a/test/parser/position_test.exs
+++ b/test/parser/position_test.exs
@@ -20,6 +20,24 @@ defmodule Parser.PositionTest do
         assert result == nil or match?(%PositionStruct{latitude: nil, longitude: nil}, result)
       end
     end
+
+    test "parses position with DAO extension in comment" do
+      result = Position.parse("4903.50N/07201.75W>Test!ABZ! position")
+      assert %PositionStruct{} = result
+      assert result.dao == %{lat_dao: "A", lon_dao: "B", datum: "WGS84"}
+    end
+
+    test "parses ambiguous position (spaces in lat/lon)" do
+      result = Position.parse("49 3.50N/07201.7 W>Ambiguous")
+      assert %PositionStruct{} = result
+      assert result.position_ambiguity == 1
+    end
+
+    test "returns struct with nil lat/lon for structurally valid but invalid lat/lon" do
+      # Valid length but not matching regex
+      result = Position.parse("abcdefgh/ijklmnopq>Invalid")
+      assert %PositionStruct{latitude: nil, longitude: nil} = result
+    end
   end
 
   property "returns nil or struct with nil lat/lon for random invalid strings" do
@@ -45,6 +63,17 @@ defmodule Parser.PositionTest do
     test "returns nils for invalid strings" do
       assert %{latitude: nil, longitude: nil} = Position.parse_aprs_position("bad", "data")
     end
+
+    test "parses southern and eastern hemispheres" do
+      result = Position.parse_aprs_position("1234.56S", "04540.70E")
+      assert Decimal.compare(result.latitude, Decimal.new(0)) == :lt
+      assert Decimal.compare(result.longitude, Decimal.new(0)) == :gt
+    end
+
+    test "returns nil for malformed but structurally valid input" do
+      result = Position.parse_aprs_position("12345678", "123456789")
+      assert %{latitude: nil, longitude: nil} = result
+    end
   end
 
   describe "calculate_position_ambiguity/2" do
diff --git a/test/support/mock_helpers.ex b/test/support/mock_helpers.ex
index 25afc61..6efe0d9 100644
--- a/test/support/mock_helpers.ex
+++ b/test/support/mock_helpers.ex
@@ -3,14 +3,7 @@ defmodule Aprs.MockHelpers do
   Provides mocks and stubs for tests.
   """
 
-  alias Aprs.BadPacket
-
   def stub_packets_mock do
-    # Only define the mock if it doesn't already exist
-    if !Code.ensure_loaded?(PacketsMock) do
-      Mox.defmock(PacketsMock, for: Aprs.PacketsBehaviour)
-    end
-
     Mox.stub(PacketsMock, :get_historical_packet_count, fn _opts -> 0 end)
     Mox.stub(PacketsMock, :stream_packets_for_replay, fn _opts -> [] end)
     Mox.stub(PacketsMock, :get_packets_for_replay, fn _opts -> [] end)
@@ -20,10 +13,6 @@ defmodule Aprs.MockHelpers do
   end
 
   def stub_badpackets_mock do
-    if !Code.ensure_loaded?(BadPacketsMock) do
-      Mox.defmock(BadPacketsMock, for: BadPacket)
-    end
-
     Mox.stub_with(BadPacketsMock, BadPacketsStub)
   end
 end
diff --git a/test/test_helper.exs b/test/test_helper.exs
index dfe59c1..6e7c17c 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -4,6 +4,7 @@ Ecto.Adapters.SQL.Sandbox.mode(Aprs.Repo, :manual)
 # Configure Mox
 Mox.defmock(Aprs.PacketsMock, for: Aprs.PacketsBehaviour)
 Mox.defmock(Aprs.PacketReplayMock, for: Aprs.PacketReplayBehaviour)
+Mox.defmock(PacketsMock, for: Aprs.PacketsBehaviour)
 
 # Ensure no external APRS connections during tests
 Application.put_env(:aprs, :disable_aprs_connection, true)