Add code coverage

.github/workflows/ci.yml

@@ -11,6 +11,8 @@ jobs:
     runs-on: ubuntu-20.04
     env:
       MIX_ENV: test
+      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
     strategy:
       fail-fast: false
       matrix:
@@ -22,34 +24,59 @@ jobs:
               elixir: "1.16"
               otp: "26.2"
             lint: lint
+            coverage: coverage
     steps:
-      - uses: actions/checkout@v4
+      - name: Check out this repository
+        uses: actions/checkout@v4
 
-      - uses: erlef/setup-beam@v1
+      - name: Set up Erlang and Elixir
+        uses: erlef/setup-beam@v1
         with:
-          otp-version: ${{matrix.pair.otp}}
-          elixir-version: ${{matrix.pair.elixir}}
+          otp-version: ${{ matrix.pair.otp }}
+          elixir-version: ${{ matrix.pair.elixir }}
 
-      - uses: actions/cache@v4
+      - name: Restored cached Mix dependencies (downloaded and compiled)
+        uses: actions/cache/restore@v4
+        id: restore-mix-deps-cache
         with:
           path: |
             deps
             _build
-          key: ${{ runner.os }}-mix-${{matrix.pair.elixir}}-${{matrix.pair.otp}}-${{ hashFiles('**/mix.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-mix-
+          key: |
+            ${{ runner.os }}-mix-${{ matrix.pair.elixir }}-${{ matrix.pair.otp }}-${{ hashFiles('**/mix.lock') }}-${{ github.run_id }}
+            restore-keys: |
+            ${{ runner.os }}-mix-${{ matrix.pair.elixir }}-${{ matrix.pair.otp }}-${{ hashFiles('**/mix.lock') }}-
+            ${{ runner.os }}-mix-${{ matrix.pair.elixir }}-${{ matrix.pair.otp }}-
 
-      - run: mix deps.get --check-locked
+      - name: Fetch and compile Mix dependencies
+        run: mix do deps.get --check-locked, deps.compile
 
-      - run: mix format --check-formatted
-        if: ${{ matrix.lint }}
+      - name: Cache compiled Mix dependencies
+        uses: actions/cache/save@v4
+        with:
+          path: |
+            deps
+            _build
+          key: ${{ steps.restore-mix-deps-cache.outputs.cache-primary-key }}
 
-      - run: mix deps.unlock --check-unused
+      - name: Check for formatted files
+        run: mix format --check-formatted
         if: ${{ matrix.lint }}
 
-      - run: mix deps.compile
+      - name: Check for unused dependencies
+        run: mix deps.unlock --check-unused
+        if: ${{ matrix.lint }}
 
-      - run: mix compile --warnings-as-errors
+      - name: Check compilation warnings
+        run: mix compile --warnings-as-errors
         if: ${{ matrix.lint }}
 
-      - run: mix test
+      # We always need to run tests because code coverage forces us to skip some
+      # tests, so better to run normal tests on the whole matrix and the coverage
+      # only on the latest version.
+      - name: Run tests
+        run: mix test
+
+      - name: Run tests with coverage
+        if: ${{ matrix.coverage }}
+        run: mix coveralls.github --exclude fails_on_coverage

mix.exs

@@ -14,7 +14,14 @@ defmodule Mox.MixProject do
       description: "Mocks and explicit contracts for Elixir",
       deps: deps(),
       docs: docs(),
-      package: package()
+      package: package(),
+      test_coverage: [tool: ExCoveralls],
+      preferred_cli_env: [
+        coveralls: :test,
+        "coveralls.detail": :test,
+        "coveralls.post": :test,
+        "coveralls.html": :test
+      ]
     ]
   end
 
@@ -30,8 +37,10 @@ defmodule Mox.MixProject do
 
   defp deps do
     [
-      {:nimble_ownership, "~> 0.3.0"},
-      {:ex_doc, "~> 0.16", only: :docs}
+      {:nimble_ownership, "~> 0.3"},
+      {:castore, "~> 1.0", only: :test},
+      {:ex_doc, "~> 0.16", only: :docs},
+      {:excoveralls, "~> 0.18", only: :test}
     ]
   end
 

mix.lock

@@ -1,9 +1,12 @@
 %{
+  "castore": {:hex, :castore, "1.0.5", "9eeebb394cc9a0f3ae56b813459f990abb0a3dedee1be6b27fdb50301930502f", [:mix], [], "hexpm", "8d7c597c3e4a64c395980882d4bca3cebb8d74197c590dc272cfd3b6a6310578"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.26", "f4291134583f373c7d8755566122908eb9662df4c4b63caa66a0eabe06569b0a", [:mix], [], "hexpm", "48d460899f8a0c52c5470676611c01f64f3337bad0b26ddab43648428d94aabc"},
   "ex_doc": {:hex, :ex_doc, "0.28.5", "3e52a6d2130ce74d096859e477b97080c156d0926701c13870a4e1f752363279", [:mix], [{:earmark_parser, "~> 1.4.19", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1", [hex: :makeup_erlang, repo: "hexpm", optional: false]}], "hexpm", "d2c4b07133113e9aa3e9ba27efb9088ba900e9e51caa383919676afdf09ab181"},
+  "excoveralls": {:hex, :excoveralls, "0.18.0", "b92497e69465dc51bc37a6422226ee690ab437e4c06877e836f1c18daeb35da9", [:mix], [{:castore, "~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "1109bb911f3cb583401760be49c02cbbd16aed66ea9509fc5479335d284da60b"},
+  "jason": {:hex, :jason, "1.4.1", "af1504e35f629ddcdd6addb3513c3853991f694921b1b9368b0bd32beb9f1b63", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "fbb01ecdfd565b56261302f7e1fcc27c4fb8f32d56eab74db621fc154604a7a1"},
   "makeup": {:hex, :makeup, "1.1.0", "6b67c8bc2882a6b6a445859952a602afc1a41c2e08379ca057c0f525366fc3ca", [:mix], [{:nimble_parsec, "~> 1.2.2 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "0a45ed501f4a8897f580eabf99a2e5234ea3e75a4373c8a52824f6e873be57a6"},
   "makeup_elixir": {:hex, :makeup_elixir, "0.16.0", "f8c570a0d33f8039513fbccaf7108c5d750f47d8defd44088371191b76492b0b", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.2.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "28b2cbdc13960a46ae9a8858c4bebdec3c9a6d7b4b9e7f4ed1502f8159f338e7"},
   "makeup_erlang": {:hex, :makeup_erlang, "0.1.1", "3fcb7f09eb9d98dc4d208f49cc955a34218fc41ff6b84df7c75b3e6e533cc65f", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "174d0809e98a4ef0b3309256cbf97101c6ec01c4ab0b23e926a9e17df2077cbb"},
-  "nimble_ownership": {:hex, :nimble_ownership, "0.3.0", "29514f8779b26f50f9c07109677c98c0cc0b8025e89f82964dafa9cf7d657ec0", [:mix], [], "hexpm", "76c605106bc1e60f5b028b20203a1e0c90b4350b08e4b8a33f68bb50dcb6e837"},
+  "nimble_ownership": {:hex, :nimble_ownership, "0.3.1", "99d5244672fafdfac89bfad3d3ab8f0d367603ce1dc4855f86a1c75008bce56f", [:mix], [], "hexpm", "4bf510adedff0449a1d6e200e43e57a814794c8b5b6439071274d248d272a549"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.2.3", "244836e6e3f1200c7f30cb56733fd808744eca61fd182f731eac4af635cc6d0b", [:mix], [], "hexpm", "c8d789e39b9131acf7b99291e93dae60ab48ef14a7ee9d58c6964f59efb570b0"},
 }

test/cluster_test.exs

@@ -10,6 +10,9 @@ if otp_release >= 25 do
     use ExUnit.Case
     import Mox
 
+    # These tests don't work if code coverage is enabled.
+    @moduletag :fails_on_coverage
+
     setup_all do
       Task.start_link(fn ->
         System.cmd("epmd", [])