diff --git a/test/microwaveprop/markdown_test.exs b/test/microwaveprop/markdown_test.exs
new file mode 100644
index 00000000..d072a810
--- /dev/null
+++ b/test/microwaveprop/markdown_test.exs
@@ -0,0 +1,169 @@
+defmodule Microwaveprop.MarkdownTest do
+  use ExUnit.Case, async: true
+
+  alias Microwaveprop.Markdown
+
+  describe "headings" do
+    test "renders h1" do
+      assert Markdown.to_html!("# Hello") =~ "<h1>Hello</h1>"
+    end
+
+    test "renders h2 through h6" do
+      for level <- 2..6 do
+        hashes = String.duplicate("#", level)
+        assert Markdown.to_html!("#{hashes} Title") =~ "<h#{level}>Title</h#{level}>"
+      end
+    end
+
+    test "caps at h6 for excessive hashes" do
+      assert Markdown.to_html!("####### Too many") =~ "<h6>"
+    end
+  end
+
+  describe "paragraphs" do
+    test "renders simple paragraph" do
+      assert Markdown.to_html!("Hello world") =~ "<p>Hello world</p>"
+    end
+
+    test "joins multi-line paragraphs" do
+      result = Markdown.to_html!("Line one\nLine two")
+      assert result =~ "<p>Line one Line two</p>"
+    end
+
+    test "separates paragraphs by blank lines" do
+      result = Markdown.to_html!("Para one\n\nPara two")
+      assert result =~ "<p>Para one</p>"
+      assert result =~ "<p>Para two</p>"
+    end
+  end
+
+  describe "fenced code blocks" do
+    test "renders code block" do
+      md = "```\nfoo\nbar\n```"
+      result = Markdown.to_html!(md)
+      assert result =~ "<pre><code>foo\nbar</code></pre>"
+    end
+
+    test "renders code block with language" do
+      md = "```elixir\nIO.puts(\"hi\")\n```"
+      result = Markdown.to_html!(md)
+      assert result =~ ~s(<code class="language-elixir">)
+    end
+
+    test "escapes HTML in code blocks" do
+      md = "```\n<script>alert('xss')</script>\n```"
+      result = Markdown.to_html!(md)
+      assert result =~ "&lt;script&gt;"
+      refute result =~ "<script>"
+    end
+  end
+
+  describe "tables" do
+    test "renders table with header" do
+      md = "| A | B |\n|---|---|\n| 1 | 2 |"
+      result = Markdown.to_html!(md)
+      assert result =~ "<thead>"
+      assert result =~ "<th>A</th>"
+      assert result =~ "<td>1</td>"
+    end
+  end
+
+  describe "lists" do
+    test "renders unordered list" do
+      md = "- one\n- two\n- three"
+      result = Markdown.to_html!(md)
+      assert result =~ "<ul>"
+      assert result =~ "<li>one</li>"
+      assert result =~ "<li>two</li>"
+      assert result =~ "<li>three</li>"
+    end
+
+    test "renders ordered list" do
+      md = "1. first\n2. second"
+      result = Markdown.to_html!(md)
+      assert result =~ "<ol>"
+      assert result =~ "<li>first</li>"
+      assert result =~ "<li>second</li>"
+    end
+  end
+
+  describe "inline formatting" do
+    test "renders bold with **" do
+      assert Markdown.to_html!("**bold**") =~ "<strong>bold</strong>"
+    end
+
+    test "renders bold with __" do
+      assert Markdown.to_html!("__bold__") =~ "<strong>bold</strong>"
+    end
+
+    test "renders italic with *" do
+      assert Markdown.to_html!("*italic*") =~ "<em>italic</em>"
+    end
+
+    test "renders inline code" do
+      assert Markdown.to_html!("`code`") =~ "<code>code</code>"
+    end
+
+    test "renders links" do
+      assert Markdown.to_html!("[text](http://example.com)") =~ ~s(<a href="http://example.com">text</a>)
+    end
+  end
+
+  describe "list continuation" do
+    test "continues unordered list items with indentation" do
+      md = "- item one\n  continued\n- item two"
+      result = Markdown.to_html!(md)
+      assert result =~ "<li>item one continued</li>"
+      assert result =~ "<li>item two</li>"
+    end
+  end
+
+  describe "table without separator" do
+    test "renders table body only when no separator row" do
+      md = "| A | B |"
+      result = Markdown.to_html!(md)
+      assert result =~ "<tbody>"
+      refute result =~ "<thead>"
+    end
+  end
+
+  describe "CRLF handling" do
+    test "normalizes CRLF to LF" do
+      result = Markdown.to_html!("Hello\r\nworld")
+      assert result =~ "<p>Hello world</p>"
+    end
+  end
+
+  describe "empty input" do
+    test "handles empty string" do
+      assert Markdown.to_html!("") == ""
+    end
+  end
+
+  describe "horizontal rules" do
+    test "renders --- as hr" do
+      assert Markdown.to_html!("---") =~ "<hr />"
+    end
+
+    test "renders *** as hr" do
+      assert Markdown.to_html!("***") =~ "<hr />"
+    end
+
+    test "renders ___ as hr" do
+      assert Markdown.to_html!("___") =~ "<hr />"
+    end
+  end
+
+  describe "HTML escaping" do
+    test "escapes angle brackets in paragraphs" do
+      result = Markdown.to_html!("x < y > z")
+      assert result =~ "&lt;"
+      assert result =~ "&gt;"
+    end
+
+    test "escapes ampersands" do
+      result = Markdown.to_html!("a & b")
+      assert result =~ "&amp;"
+    end
+  end
+end
diff --git a/test/microwaveprop/radio/enrichment_status_test.exs b/test/microwaveprop/radio/enrichment_status_test.exs
new file mode 100644
index 00000000..515a5439
--- /dev/null
+++ b/test/microwaveprop/radio/enrichment_status_test.exs
@@ -0,0 +1,130 @@
+defmodule Microwaveprop.Radio.EnrichmentStatusTest do
+  use Microwaveprop.DataCase, async: true
+
+  alias Microwaveprop.Radio.Contact
+  alias Microwaveprop.Radio.EnrichmentStatus
+
+  describe "states/0" do
+    test "returns all valid states" do
+      assert EnrichmentStatus.states() == [:pending, :queued, :processing, :complete, :failed, :unavailable]
+    end
+  end
+
+  describe "fields/0" do
+    test "returns all status fields" do
+      assert EnrichmentStatus.fields() == [:hrrr_status, :weather_status, :terrain_status, :iemre_status]
+    end
+  end
+
+  describe "valid_transition?/2" do
+    test "pending can transition to queued" do
+      assert EnrichmentStatus.valid_transition?(:pending, :queued)
+    end
+
+    test "pending can transition to unavailable" do
+      assert EnrichmentStatus.valid_transition?(:pending, :unavailable)
+    end
+
+    test "pending cannot transition to complete" do
+      refute EnrichmentStatus.valid_transition?(:pending, :complete)
+    end
+
+    test "queued can transition to processing" do
+      assert EnrichmentStatus.valid_transition?(:queued, :processing)
+    end
+
+    test "queued can transition to failed" do
+      assert EnrichmentStatus.valid_transition?(:queued, :failed)
+    end
+
+    test "queued cannot transition to complete" do
+      refute EnrichmentStatus.valid_transition?(:queued, :complete)
+    end
+
+    test "processing can transition to complete" do
+      assert EnrichmentStatus.valid_transition?(:processing, :complete)
+    end
+
+    test "processing can transition to failed" do
+      assert EnrichmentStatus.valid_transition?(:processing, :failed)
+    end
+
+    test "processing cannot transition to pending" do
+      refute EnrichmentStatus.valid_transition?(:processing, :pending)
+    end
+
+    test "failed can transition to queued (retry)" do
+      assert EnrichmentStatus.valid_transition?(:failed, :queued)
+    end
+
+    test "failed cannot transition to complete" do
+      refute EnrichmentStatus.valid_transition?(:failed, :complete)
+    end
+
+    test "unavailable can transition to queued (retry)" do
+      assert EnrichmentStatus.valid_transition?(:unavailable, :queued)
+    end
+
+    test "complete can transition to pending (reset)" do
+      assert EnrichmentStatus.valid_transition?(:complete, :pending)
+    end
+
+    test "complete cannot transition to queued" do
+      refute EnrichmentStatus.valid_transition?(:complete, :queued)
+    end
+  end
+
+  describe "transition/3" do
+    test "applies valid transition to changeset" do
+      changeset =
+        %Contact{}
+        |> Ecto.Changeset.change(%{hrrr_status: :pending})
+        |> EnrichmentStatus.transition(:hrrr_status, :queued)
+
+      assert Ecto.Changeset.get_change(changeset, :hrrr_status) == :queued
+      assert changeset.valid?
+    end
+
+    test "adds error for invalid transition" do
+      changeset =
+        %Contact{}
+        |> Ecto.Changeset.change(%{hrrr_status: :pending})
+        |> EnrichmentStatus.transition(:hrrr_status, :complete)
+
+      assert {:hrrr_status, {"invalid transition from pending to complete", []}} in changeset.errors
+    end
+
+    test "works for all status fields" do
+      for field <- EnrichmentStatus.fields() do
+        changeset =
+          %Contact{}
+          |> Ecto.Changeset.change(%{field => :pending})
+          |> EnrichmentStatus.transition(field, :queued)
+
+        assert Ecto.Changeset.get_change(changeset, field) == :queued
+      end
+    end
+  end
+
+  describe "force_status/3" do
+    test "sets status without transition validation" do
+      changeset =
+        %Contact{}
+        |> Ecto.Changeset.change(%{hrrr_status: :pending})
+        |> EnrichmentStatus.force_status(:hrrr_status, :complete)
+
+      assert Ecto.Changeset.get_change(changeset, :hrrr_status) == :complete
+      assert changeset.valid?
+    end
+
+    test "allows normally invalid transitions" do
+      changeset =
+        %Contact{}
+        |> Ecto.Changeset.change(%{weather_status: :pending})
+        |> EnrichmentStatus.force_status(:weather_status, :failed)
+
+      assert Ecto.Changeset.get_change(changeset, :weather_status) == :failed
+      assert changeset.valid?
+    end
+  end
+end
diff --git a/test/microwaveprop/radio/maidenhead_test.exs b/test/microwaveprop/radio/maidenhead_test.exs
index b60e8bf1..96238117 100644
--- a/test/microwaveprop/radio/maidenhead_test.exs
+++ b/test/microwaveprop/radio/maidenhead_test.exs
@@ -77,6 +77,19 @@ defmodule Microwaveprop.Radio.MaidenheadTest do
       assert :error = Maidenhead.to_latlon(nil)
     end
 
+    test "returns :error for non-binary" do
+      assert :error = Maidenhead.to_latlon(123)
+    end
+
+    test "handles 8-char extended grid EM12kp37" do
+      assert {:ok, {lat, lon}} = Maidenhead.to_latlon("EM12kp37")
+      assert is_float(lat)
+      assert is_float(lon)
+      # Should be within EM12kp subsquare
+      assert lat > 32.0 and lat < 33.0
+      assert lon > -98.0 and lon < -96.0
+    end
+
     test "AA00 returns southwest corner center" do
       # lon = 0*20 - 180 + 0*2 + 1 = -179, lat = 0*10 - 90 + 0*1 + 0.5 = -89.5
       assert {:ok, {lat, lon}} = Maidenhead.to_latlon("AA00")
diff --git a/test/microwaveprop_web/controllers/health_controller_test.exs b/test/microwaveprop_web/controllers/health_controller_test.exs
new file mode 100644
index 00000000..b3448210
--- /dev/null
+++ b/test/microwaveprop_web/controllers/health_controller_test.exs
@@ -0,0 +1,10 @@
+defmodule MicrowavepropWeb.HealthControllerTest do
+  use MicrowavepropWeb.ConnCase, async: true
+
+  test "GET /health returns 200 ok", %{conn: conn} do
+    conn = get(conn, "/health")
+
+    assert response(conn, 200) == "ok"
+    assert response_content_type(conn, :text) =~ "text/plain"
+  end
+end
diff --git a/test/microwaveprop_web/plugs/remote_ip_test.exs b/test/microwaveprop_web/plugs/remote_ip_test.exs
new file mode 100644
index 00000000..76648309
--- /dev/null
+++ b/test/microwaveprop_web/plugs/remote_ip_test.exs
@@ -0,0 +1,83 @@
+defmodule MicrowavepropWeb.Plugs.RemoteIpTest do
+  use ExUnit.Case, async: true
+
+  import Plug.Conn
+  import Plug.Test
+
+  alias MicrowavepropWeb.Plugs.RemoteIp
+
+  defp call_plug(conn) do
+    RemoteIp.call(conn, RemoteIp.init([]))
+  end
+
+  describe "call/2" do
+    test "extracts IP from cf-connecting-ip header" do
+      conn =
+        conn(:get, "/")
+        |> put_req_header("cf-connecting-ip", "1.2.3.4")
+        |> call_plug()
+
+      assert conn.remote_ip == {1, 2, 3, 4}
+    end
+
+    test "falls back to x-forwarded-for when no cf-connecting-ip" do
+      conn =
+        conn(:get, "/")
+        |> put_req_header("x-forwarded-for", "5.6.7.8")
+        |> call_plug()
+
+      assert conn.remote_ip == {5, 6, 7, 8}
+    end
+
+    test "prefers cf-connecting-ip over x-forwarded-for" do
+      conn =
+        conn(:get, "/")
+        |> put_req_header("cf-connecting-ip", "1.2.3.4")
+        |> put_req_header("x-forwarded-for", "5.6.7.8")
+        |> call_plug()
+
+      assert conn.remote_ip == {1, 2, 3, 4}
+    end
+
+    test "takes first IP from comma-separated x-forwarded-for" do
+      conn =
+        conn(:get, "/")
+        |> put_req_header("x-forwarded-for", "10.0.0.1, 10.0.0.2, 10.0.0.3")
+        |> call_plug()
+
+      assert conn.remote_ip == {10, 0, 0, 1}
+    end
+
+    test "preserves original remote_ip when no headers present" do
+      original_ip = {127, 0, 0, 1}
+
+      conn =
+        conn(:get, "/")
+        |> Map.put(:remote_ip, original_ip)
+        |> call_plug()
+
+      assert conn.remote_ip == original_ip
+    end
+
+    test "handles IPv6 addresses" do
+      conn =
+        conn(:get, "/")
+        |> put_req_header("cf-connecting-ip", "::1")
+        |> call_plug()
+
+      assert conn.remote_ip == {0, 0, 0, 0, 0, 0, 0, 1}
+    end
+
+    test "ignores malformed IP addresses" do
+      original_ip = {127, 0, 0, 1}
+
+      conn =
+        conn(:get, "/")
+        |> Map.put(:remote_ip, original_ip)
+        |> put_req_header("cf-connecting-ip", "not-an-ip")
+        |> call_plug()
+
+      assert conn.remote_ip == original_ip
+    end
+  end
+end