Expand travis matrix and update Makefile (#92)

* Expand travis matrix and update Makefile

* Correct spec

.travis.yml

@@ -4,15 +4,36 @@ notifications:
   email: false
 
 elixir:
-  - 1.6
+  - 1.8
+  - 1.7
 
 otp_release:
+  - 21.1
   - 20.3
-  - 21.0
+  - 19.3
+  - 18.3
+
+matrix:
+  exclude:
+    - elixir: 1.8
+      otp_release: 19.3
+    - elixir: 1.8
+      otp_release: 18.3
+
+before_script:
+  - travis_wait mix dialyzer --plt
 
 script:
   - make testing
+
+cache:
+  directories:
+    - _build
+    - deps
+    - priv/plts
+
 after_script:
   - make docs
+
 after_success:
   - bash <(curl -s https://codecov.io/bash)

Makefile

@@ -4,9 +4,11 @@ deps:
 	mix deps.get
 
 testing: deps
-	mix credo
+	mix do compile --warnings-as-errors --force
 	mix format --check-formatted
+	mix credo
 	MIX_ENV=test mix coveralls.json
+	mix dialyzer --halt-exit-status
 
 docs:
 	mix inch.report

lib/ueberauth/strategies/helpers.ex

@@ -67,7 +67,7 @@ defmodule Ueberauth.Strategy.Helpers do
 
   This method will filter conn.params with whitelisted params from :callback_params settings
   """
-  @spec callback_params(Plug.Conn.t()) :: list(String.t())
+  @spec callback_params(Plug.Conn.t()) :: keyword()
   def callback_params(conn, opts \\ []) do
     callback_params = from_private(conn, :callback_params) || []