diff --git a/.travis.yml b/.travis.yml
index 3bf7c510..a1fe441d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,10 +9,11 @@ services:
   - docker
 
 before_install:
-  - docker run -d -p 2197:2197 mobify/apns-http2-mock-server
-  - docker run -d -p 443:443 roxeon/fcm-http2-mock-server
+  - tools/travis-setup.sh
 
 env:
-    - MIX_ENV=test
+    - PRESET=exunit MIX_ENV=test
+    - PRESET=credo MIX_ENV=test
+    - PRESET=dialyzer MIX=test
 
-script: mix coveralls.travis
+script: tools/travis-test.sh
diff --git a/Makefile b/Makefile
index 1fff41d2..b5059fa1 100644
--- a/Makefile
+++ b/Makefile
@@ -11,14 +11,21 @@ compile:
 	mix compile
 
 certs: priv/ssl/fake_cert.pem priv/ssl/fake_server.pem priv/ssl/fake_dh_server.pem \
-       priv/apns/app_cert.pem
+       priv/apns/dev_cert.pem priv/apns/prod_cert.pem
 
-priv/apns/app_cert.pem:
+priv/apns/prod_cert.pem:
 	@mkdir -p $(@D)
 	openssl req \
     	-x509 -nodes -days 365 \
-    	-subj '/C=PL/ST=ML/L=Krakow/CN=mongoose-push-apns' \
-    	-newkey rsa:2048 -keyout priv/apns/app_key.pem -out priv/apns/app_cert.pem
+    	-subj '/C=PL/ST=ML/L=Krakow/CN=mongoose-push-apns-prod' \
+    	-newkey rsa:2048 -keyout priv/apns/prod_key.pem -out priv/apns/prod_cert.pem
+
+priv/apns/dev_cert.pem:
+	@mkdir -p $(@D)
+	openssl req \
+			-x509 -nodes -days 365 \
+			-subj '/C=PL/ST=ML/L=Krakow/CN=mongoose-push-apns-dev' \
+			-newkey rsa:2048 -keyout priv/apns/dev_key.pem -out priv/apns/dev_cert.pem
 
 priv/ssl/fake_cert.pem:
 	@mkdir -p $(@D)
diff --git a/lib/mongoose_push/application.ex b/lib/mongoose_push/application.ex
index 823d8d03..b3b933a5 100644
--- a/lib/mongoose_push/application.ex
+++ b/lib/mongoose_push/application.ex
@@ -49,16 +49,16 @@ defmodule MongoosePush.Application do
   def pool_size(type, name), do: env(type)[name][:pool_size]
   def worker_name(type, name, num), do: String.to_atom(~s"#{type}_#{name}_#{num}")
 
-  def pools_by_mode(service, mode) when is_atom(service) do
-    pools_by_mode(env(service), mode)
-  end
+  def pools_by_mode(:fcm = service, _mode) do
+    config = env(service)
 
-  def pools_by_mode(config, _mode) do
     config
     |> Enum.map(&(elem(&1, 0)))
   end
 
-  def pools_by_mode(config, mode) do
+  def pools_by_mode(:apns = service, mode) do
+    config = env(service)
+    
     config
     |> Enum.group_by(&(elem(&1, 1)[:mode]), &(elem &1, 0))
     |> Map.get(mode)
diff --git a/mix.exs b/mix.exs
index 89ce3086..d78b8b8e 100644
--- a/mix.exs
+++ b/mix.exs
@@ -38,7 +38,7 @@ defmodule MongoosePush.Mixfile do
      {:httpoison, "~> 0.10.0"},
      {:mock, "~> 0.2.0", only: :test},
      {:excoveralls, "~> 0.6", only: :test},
-     {:dialyxir, "~> 0.4", only: [:dev], runtime: false},
+     {:dialyxir, "~> 0.4", only: [:dev, :test], runtime: false},
      {:credo, "~> 0.5", only: [:dev, :test]}
     ]
   end
diff --git a/tools/travis-setup.sh b/tools/travis-setup.sh
new file mode 100755
index 00000000..75f23236
--- /dev/null
+++ b/tools/travis-setup.sh
@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+set -e
+
+# Skip this setup for jobs that don't run exunit
+test "${PRESET}" == "exunit" || exit 0
+
+docker run -d -p 2197:2197 mobify/apns-http2-mock-server
+docker run -d -p 443:443 roxeon/fcm-http2-mock-server
diff --git a/tools/travis-test.sh b/tools/travis-test.sh
new file mode 100755
index 00000000..07a0a9f6
--- /dev/null
+++ b/tools/travis-test.sh
@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -e
+
+case "${PRESET}" in
+  "exunit" )
+    mix coveralls.travis
+    ;;
+  "dialyzer" )
+    mix dialyzer
+    ;;
+  "credo" )
+    mix credo --ignore design
+    ;;
+  * )
+    echo "Unknown PRESET value" || exit 1
+esac