diff --git a/.github/workflows/elixir.yml b/.github/workflows/elixir.yml
new file mode 100644
index 0000000..646bcdf
--- /dev/null
+++ b/.github/workflows/elixir.yml
@@ -0,0 +1,35 @@
+name: Elixir CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    name: Build and test
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: System dependencies
+      run: |
+        sudo apt update
+        sudo apt install -y inotify-tools
+    - name: Set up Elixir
+      uses: erlef/setup-beam@988e02bfe678367a02564f65ca2e37726dc0268f
+      with:
+        elixir-version: '1.12.3' # Define the elixir version [required]
+        otp-version: '24.1' # Define the OTP version [required]
+    - name: Restore dependencies cache
+      uses: actions/cache@v2
+      with:
+        path: deps
+        key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}
+        restore-keys: ${{ runner.os }}-mix-
+    - name: Install dependencies
+      run: mix deps.get
+    - name: Run tests
+      run: mix test
diff --git a/lib/koans/17_agents.ex b/lib/koans/17_agents.ex
index ec0ce28..c6e17f2 100644
--- a/lib/koans/17_agents.ex
+++ b/lib/koans/17_agents.ex
@@ -14,31 +14,31 @@ defmodule Agents do
   end
 
   koan "Update to update the state" do
-    Agent.start_link(fn -> "Hi there" end, name: __MODULE__)
+    Agent.start_link(fn -> "Hi there" end, name: :greeter)
 
-    Agent.update(__MODULE__, fn old ->
+    Agent.update(:greeter, fn old ->
       String.upcase(old)
     end)
 
-    assert Agent.get(__MODULE__, & &1) == ___
+    assert Agent.get(:greeter, & &1) == ___
   end
 
   koan "Use get_and_update when you need to read and change a value in one go" do
-    Agent.start_link(fn -> ["Milk"] end, name: __MODULE__)
+    Agent.start_link(fn -> ["Milk"] end, name: :groceries)
 
     old_list =
-      Agent.get_and_update(__MODULE__, fn old ->
+      Agent.get_and_update(:groceries, fn old ->
         {old, ["Bread" | old]}
       end)
 
     assert old_list == ___
-    assert Agent.get(__MODULE__, & &1) == ___
+    assert Agent.get(:groceries, & &1) == ___
   end
 
   koan "Somebody has to switch off the light at the end of the day" do
-    {:ok, pid} = Agent.start_link(fn -> ["Milk"] end, name: __MODULE__)
+    {:ok, pid} = Agent.start_link(fn -> "Fin." end, name: :stoppable)
 
-    Agent.stop(__MODULE__)
+    Agent.stop(:stoppable)
 
     assert Process.alive?(pid) == ___
   end
diff --git a/lib/koans/18_genservers.ex b/lib/koans/18_genservers.ex
index 8e78761..ab6d7dc 100644
--- a/lib/koans/18_genservers.ex
+++ b/lib/koans/18_genservers.ex
@@ -12,9 +12,13 @@ defmodule GenServers do
       {:ok, args}
     end
 
-    def start_link(init_password) do
+    def start(init_password) do
       # The __MODULE__ macro returns the current module name as an atom
-      GenServer.start_link(__MODULE__, init_password, name: __MODULE__)
+      GenServer.start(__MODULE__, init_password, name: __MODULE__)
+    end
+
+    def stop do
+      GenServer.stop(__MODULE__)
     end
 
     def unlock(password) do
@@ -134,20 +138,24 @@ defmodule GenServers do
   end
 
   koan "Our server works but it's pretty ugly to use; so lets use a cleaner interface" do
-    Laptop.start_link("EL!73")
+    Laptop.start("EL!73")
     assert Laptop.unlock("EL!73") == ___
   end
 
   koan "Let's use the remaining functions in the external API" do
-    Laptop.start_link("EL!73")
+    Laptop.start("EL!73")
+
     {_, response} = Laptop.unlock("EL!73")
     assert response == ___
 
     Laptop.change_password("EL!73", "Elixir")
+
     {_, response} = Laptop.unlock("EL!73")
     assert response == ___
 
     {_, response} = Laptop.owner_name()
     assert response == ___
+
+    :ok = Laptop.stop()
   end
 end
diff --git a/test/koans/map_sets_koans_test.exs b/test/koans/map_sets_koans_test.exs
index 043001d..327ebf9 100644
--- a/test/koans/map_sets_koans_test.exs
+++ b/test/koans/map_sets_koans_test.exs
@@ -4,7 +4,6 @@ defmodule MapSetsTest do
 
   test "MapSets" do
     answers = [
-      1,
       3,
       {:multiple, [false, true]},
       true,
diff --git a/test/koans/protocols_koans_test.exs b/test/koans/protocols_koans_test.exs
index 88dcbb7..c23513a 100644
--- a/test/koans/protocols_koans_test.exs
+++ b/test/koans/protocols_koans_test.exs
@@ -4,8 +4,8 @@ defmodule ProtocolsTests do
 
   test "Protocols" do
     answers = [
-      {:multiple, ["Andre signed up for violin", "Darcy enrolled for ballet"]},
-      "Pupil enrolled at school",
+      {:multiple, ["Andre played violin", "Darcy performed ballet"]},
+      "Artist showed performance",
       Protocol.UndefinedError
     ]
 
diff --git a/test/test_helper.exs b/test/test_helper.exs
index 56d98f4..2006538 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -1,4 +1,5 @@
-ExUnit.start()
+timeout = 1000 # ms
+ExUnit.start(timeout: timeout)
 
 defmodule TestHarness do
   import ExUnit.Assertions