ci: upload coverage via excoveralls cobertura

The coverage job runs mix coveralls.cobertura on Elixir 1.20/OTP 29:
OTP 27's :cover cannot recompile 'x in [>3 items]' case guards
(erlang/otp#11524, fixed in OTP 28+), which breaks mix test --cover
and excoveralls alike, so the job pins the fixed toolchain. The
cobertura report is uploaded as an artifact and summarized on pull
requests via CodeCoverageSummary; deps caches are keyed by Elixir/OTP
version so cover can re-instrument restored beams. mix.exs gains
excoveralls, the test_coverage tool, and points @source_url at
gilbertwong96/lovely_mermaid.

Author: gilbertwong96

.github/workflows/ci.yml

@@ -45,3 +45,47 @@ jobs:
 
       - name: Quality gates
         run: mix ci
+
+  coverage:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: erlef/setup-beam@v1
+        with:
+          elixir-version: "1.20"
+          otp-version: "29"
+
+      - uses: actions/cache@v4
+        with:
+          path: |
+            deps
+            _build
+          key: ${{ runner.os }}-mix-1.20-29-${{ hashFiles('**/mix.lock') }}
+          restore-keys: ${{ runner.os }}-mix-1.20-29-
+
+      - name: Fetch dependencies
+        run: mix deps.get
+
+      - name: Generate coverage report
+        env:
+          MIX_ENV: test
+        run: mix coveralls.cobertura
+
+      - name: Upload coverage artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: cobertura.xml
+          path: cover/cobertura.xml
+
+      - name: Comment coverage summary on pull request
+        if: github.event_name == 'pull_request'
+        uses: irongut/CodeCoverageSummary@v1.3.0
+        with:
+          filename: cover/cobertura.xml
+          badge: true
+          format: markdown
+          output: both

README.md

@@ -20,13 +20,13 @@ end
 
 ## API
 
-| Function | Returns |
-|---|---|
-| `LovelyMermaid.render(src)` | `%LovelyMermaid.Art{}` (`plain`, `styled` [[span]], `width`, `class_defs`, `warnings`) or `nil` |
-| `LovelyMermaid.diagram_kind(src)` | `:flowchart \| :state \| :class \| :er \| :sequence \| :pie \| :mindmap \| :timeline \| :gitgraph \| nil` |
-| `LovelyMermaid.SourceBox.source_box(src, max_width \\ nil)` | Framed source lines, for when a diagram won't render |
-| `LovelyMermaid.Ansi.to_ansi(art, theme \\ Ansi.default_theme())` | ANSI-coloured lines from `art.styled` |
-| `LovelyMermaid.ClassStyle.resolve_class_style(classes, class_defs)` | Merged `classDef` style for a span, or `nil` |
+| Function                                                            | Returns                                                                                                   |
+|---------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------|
+| `LovelyMermaid.render(src)`                                         | `%LovelyMermaid.Art{}` (`plain`, `styled` [[span]], `width`, `class_defs`, `warnings`) or `nil`           |
+| `LovelyMermaid.diagram_kind(src)`                                   | `:flowchart \| :state \| :class \| :er \| :sequence \| :pie \| :mindmap \| :timeline \| :gitgraph \| nil` |
+| `LovelyMermaid.SourceBox.source_box(src, max_width \\ nil)`         | Framed source lines, for when a diagram won't render                                                      |
+| `LovelyMermaid.Ansi.to_ansi(art, theme \\ Ansi.default_theme())`    | ANSI-coloured lines from `art.styled`                                                                     |
+| `LovelyMermaid.ClassStyle.resolve_class_style(classes, class_defs)` | Merged `classDef` style for a span, or `nil`                                                              |
 
 Each `span` in `styled` is a `LovelyMermaid.Span` — `%Span{text, role}`
 with `classes` (author-assigned names from `:::name` / `class A,B name`)

mix.exs

@@ -2,7 +2,7 @@ defmodule LovelyMermaid.MixProject do
   use Mix.Project
 
   @version "0.1.0"
-  @source_url "https://github.com/gilbertwong/lovely_mermaid"
+  @source_url "https://github.com/gilbertwong96/lovely_mermaid"
 
   def project do
     [
@@ -16,6 +16,9 @@ defmodule LovelyMermaid.MixProject do
       # Quality gates
       dialyzer: [plt_add_apps: [:mix]],
 
+      # Coverage
+      test_coverage: [tool: ExCoveralls],
+
       # Package
       description: "Render Mermaid diagrams as Unicode box-drawing art for terminals",
       package: package(),
@@ -46,7 +49,8 @@ defmodule LovelyMermaid.MixProject do
       {:ex_slop, "~> 0.4", only: [:dev, :test], runtime: false},
       {:reach, "~> 2.8", only: [:dev, :test], runtime: false},
       {:credo, "~> 1.7", only: [:dev, :test], runtime: false},
-      {:dialyxir, "~> 1.4", only: [:dev, :test], runtime: false}
+      {:dialyxir, "~> 1.4", only: [:dev, :test], runtime: false},
+      {:excoveralls, "~> 0.18", only: :test, runtime: false}
     ]
   end
 

mix.lock

@@ -8,6 +8,7 @@
   "ex_dna": {:hex, :ex_dna, "1.5.4", "5a636109aeccca1c6df074367f53dc096f4280e90c075f5537ce8b8b4a843343", [:mix], [{:credo, "~> 1.7", [hex: :credo, repo: "hexpm", optional: true]}, {:gen_lsp, "~> 0.11", [hex: :gen_lsp, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: true]}], "hexpm", "66e6c7157127f023a219be16f2aa8e3a18c698e7a106f78bb24304b34df8034b"},
   "ex_doc": {:hex, :ex_doc, "0.40.3", "4a972ffe64bc07dc605af487e98fc19b72a4185f55ca031b94c0552d6071c1d9", [:mix], [{:earmark_parser, "~> 1.4.44", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "2756e357742fecd9749b489b85d67c9ce99c465f2e75728d9e6dc8d704b973de"},
   "ex_slop": {:hex, :ex_slop, "0.4.4", "8ca277b902e93193eb3545e414c309026a51204e5eb7d6ada5ff96555de6abcb", [:mix], [{:credo, "~> 1.7", [hex: :credo, repo: "hexpm", optional: false]}], "hexpm", "03ef1b2553ebad45c8ceb3e482eed5f1ccd08fc992215a9da0ef6196935107e2"},
+  "excoveralls": {:hex, :excoveralls, "0.18.5", "e229d0a65982613332ec30f07940038fe451a2e5b29bce2a5022165f0c9b157e", [:mix], [{:castore, "~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "523fe8a15603f86d64852aab2abe8ddbd78e68579c8525ae765facc5eae01562"},
   "file_system": {:hex, :file_system, "1.1.1", "31864f4685b0148f25bd3fbef2b1228457c0c89024ad67f7a81a3ffbc0bbad3a", [:mix], [], "hexpm", "7a15ff97dfe526aeefb090a7a9d3d03aa907e100e262a0f8f7746b78f8f87a5d"},
   "jason": {:hex, :jason, "1.4.5", "2e3a008590b0b8d7388c20293e9dcc9cf3e5d642fd2a114e4cbbb52e595d940a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "b0c823996102bcd0239b3c2444eb00409b72f6a140c1950bc8b457d836b30684"},
   "libgraph": {:hex, :libgraph, "0.16.0", "3936f3eca6ef826e08880230f806bfea13193e49bf153f93edcf0239d4fd1d07", [:mix], [], "hexpm", "41ca92240e8a4138c30a7e06466acc709b0cbb795c643e9e17174a178982d6bf"},