Add CI config

.github/workflows/elixir.yml

@@ -0,0 +1,79 @@
+name: Elixir CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+env:
+  MIX_ENV: test
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    services:
+      postgres:
+        image: postgres
+        ports:
+        - 5432:5432
+        env:
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: postgres
+
+    strategy:
+      matrix:
+        elixir: [1.12.2]
+        otp: [23.3.4.5]
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Setup Elixir
+      uses: erlef/setup-beam@v1
+      with:
+        elixir-version: ${{ matrix.elixir }} # Define the elixir version [required]
+        otp-version: ${{ matrix.otp }} # Define the OTP version [required]
+
+    - name: Retrieve Mix Dependencies Cache
+      uses: actions/cache@v1
+      id: mix-cache #id to use in retrieve action
+      with:
+        path: deps
+        key: ${{ runner.os }}-${{ matrix.otp }}-${{ matrix.elixir }}-mix-${{ hashFiles(format('{0}{1}', github.workspace, '/mix.lock')) }}
+
+    - name: Install Mix Dependencies
+      if: steps.mix-cache.outputs.cache-hit != 'true'
+      run: |
+        mix local.rebar --force
+        mix local.hex --force
+        mix deps.get
+
+    - name: Check Formatting
+      run: mix format --check-formatted
+
+    - name: Run Credo
+      run: mix credo
+
+    - name: Run Tests
+      run: mix test
+      env:
+        DATABASE_HOST: postgres
+        DATABASE_PORT: ${{ job.services.postgres.ports[5432] }}
+
+    - name: Retrieve PLT Cache
+      uses: actions/cache@v1
+      id: plt-cache
+      with:
+        path: priv/plts
+        key: ${{ runner.os }}-${{ matrix.otp }}-${{ matrix.elixir }}-plts-${{ hashFiles(format('{0}{1}', github.workspace, '/mix.lock')) }}
+
+    - name: Create PLTs
+      if: steps.plt-cache.outputs.cache-hit != 'true'
+      run: |
+        mkdir -p priv/plts
+        mix dialyzer --plt
+
+    - name: Run dialyzer
+      run: mix dialyzer --no-check --halt-exit-status

mix.exs

@@ -33,7 +33,7 @@ defmodule Snagg.MixProject do
   # Type `mix help deps` for examples and options.
   defp deps do
     [
-      {:credo, "~> 1.5", only: :dev, runtime: false},
+      {:credo, "~> 1.5", only: [:dev, :test], runtime: false},
       {:dialyxir, "~> 1.1", only: [:dev, :test], runtime: false},
       {:ecto_sql, "~> 3.6"},
       {:esbuild, "~> 0.2", runtime: Mix.env() == :dev},