diff --git a/test/chronoscope/gemini_test.exs b/test/chronoscope/gemini_test.exs
new file mode 100644
index 0000000..9cb0a79
--- /dev/null
+++ b/test/chronoscope/gemini_test.exs
@@ -0,0 +1,92 @@
+defmodule Chronoscope.GeminiTest do
+  use Chronoscope.Case, async: true
+
+  alias Chronoscope.DynamicSupervisorMock
+  alias Chronoscope.GenServerMock
+  alias Chronoscope.Gemini
+  alias Chronoscope.RegistryMock
+
+  import Mox
+
+  setup :verify_on_exit!
+
+  describe "Chronoscope.Gemini.healthy?()" do
+    test "is healthy" do
+      assert Gemini.healthy?() == true
+    end
+  end
+
+  describe "Chronoscope.Gemini.list()" do
+    test "shows empty client list" do
+      DynamicSupervisorMock
+      |> expect(:which_children, fn _ -> [] end)
+
+      assert Gemini.list() == []
+    end
+
+    test "lists all children" do
+      DynamicSupervisorMock
+      |> expect(:which_children, fn _ -> [{1, 2, 3, 4}, {5, 6, 7, 8}] end)
+
+      GenServerMock
+      |> expect(:call, fn 2, :list -> :one end)
+      |> expect(:call, fn 6, :list -> :two end)
+
+      assert Gemini.list() == [:one, :two]
+    end
+  end
+
+  describe "Chronoscope.Gemini.remove()" do
+    test "does nothing if the client doesn't exist" do
+      RegistryMock
+      |> expect(:lookup, fn _, _ -> [] end)
+
+      assert Gemini.remove("localhost", 1965, "/") == {:error, :not_found}
+    end
+
+    test "removes a client" do
+      RegistryMock
+      |> expect(:lookup, fn _, _ -> [{1, 2}] end)
+
+      GenServerMock
+      |> expect(:call, fn 1, :terminate -> :terminating end)
+
+      assert Gemini.remove("localhost", 1965, "/") == {:ok, :terminating}
+    end
+  end
+
+  describe "Chronoscope.Gemini.connect()" do
+    test "creates a new client" do
+      RegistryMock
+      |> expect(:lookup, fn _, _ -> [] end)
+
+      DynamicSupervisorMock
+      |> expect(
+        :start_child,
+        fn Chronoscope.Gemini.DynamicSupervisor,
+           {Chronoscope.Gemini.Client,
+            [
+              resource: %{host: "localhost", port: 1965, path: "/"},
+              name: {:via, RegistryMock, {Chronoscope.Gemini.Registry, "localhost:1965/"}}
+            ]} ->
+          {:ok, 1}
+        end
+      )
+
+      GenServerMock
+      |> expect(:call, fn 1, :connect -> :result end)
+
+      assert Gemini.connect("localhost", 1965, "/") == :result
+    end
+
+    test "reuses an existing client" do
+      RegistryMock
+      |> expect(:lookup, fn _, _ -> [{1, 2}] end)
+
+      GenServerMock
+      |> expect(:call, fn 1, :connect -> :result end)
+
+      assert Gemini.connect("localhost", 1965, "/") == :result
+    end
+  end
+end
diff --git a/test/chronoscope/nts_test.exs b/test/chronoscope/nts_test.exs
index 427bee3..67c75b7 100644
--- a/test/chronoscope/nts_test.exs
+++ b/test/chronoscope/nts_test.exs
@@ -61,14 +61,17 @@ defmodule Chronoscope.NTSTest do
       |> expect(:lookup, fn _, _ -> [] end)
 
       DynamicSupervisorMock
-      |> expect(:start_child, fn Chronoscope.NTS.DynamicSupervisor,
-                                 {Chronoscope.NTS.Client,
-                                  [
-                                    server: %{host: "localhost", port: 1111},
-                                    name: {:via, RegistryMock, {Chronoscope.NTS.Registry, "localhost:1111"}}
-                                  ]} ->
-        {:ok, 1}
-      end)
+      |> expect(
+        :start_child,
+        fn Chronoscope.NTS.DynamicSupervisor,
+           {Chronoscope.NTS.Client,
+            [
+              server: %{host: "localhost", port: 1111},
+              name: {:via, RegistryMock, {Chronoscope.NTS.Registry, "localhost:1111"}}
+            ]} ->
+          {:ok, 1}
+        end
+      )
 
       GenServerMock
       |> expect(:call, fn 1, :key_establishment -> :result end)