Add rspec and some basic tests

.github/workflows/rspec.yaml

@@ -0,0 +1,24 @@
+name: Rspec
+on:
+  - push
+  - pull_request
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+env:
+  ruby: '3.5'
+jobs:
+  rspec:
+    name: Rspec
+    runs-on: ubuntu-latest
+    steps:
+    - name: Check out code
+      uses: actions/checkout@v4
+    - name: Setup ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ env.ruby }}
+        rubygems: 3.4.10
+        bundler-cache: true
+    - name: Run rspec
+      run: bundle exec rspec

.rspec

@@ -0,0 +1 @@
+--require spec_helper

.rubocop.yml

@@ -1,6 +1,9 @@
 ---
 inherit_from: .rubocop_todo.yml
 
+plugins:
+  - rubocop-rspec
+
 AllCops:
   TargetRubyVersion: 2.7
 

.rubocop_todo.yml

@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2025-09-19 19:11:34 UTC using RuboCop version 1.80.2.
+# on 2025-11-28 15:41:06 UTC using RuboCop version 1.81.7.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -36,6 +36,11 @@ Naming/AccessorMethodName:
   Exclude:
     - 'lib/glug/layer.rb'
 
+# Offense count: 1
+# Configuration parameters: CountAsOne.
+RSpec/ExampleLength:
+  Max: 53
+
 # Offense count: 1
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: EnforcedStyle.

Gemfile

@@ -2,4 +2,8 @@
 
 source 'https://rubygems.org'
 
+gem 'rspec'
 gem 'rubocop', require: false
+gem 'rubocop-rspec', require: false
+
+gemspec

spec/lib/glug/stylesheet_spec.rb

@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+describe Glug::Stylesheet do
+  it 'processes a basic stylesheet' do
+    json = described_class.new do
+      version 8
+      center [0.5, 53]
+    end.to_json
+    expect(json).to eql('{"version":8,"center":[0.5,53],"sources":{},"layers":[]}')
+  end
+
+  it 'processes the example stylesheet' do
+    json = described_class.new do
+      version 8
+      name 'My first stylesheet'
+      source :shortbread, type: 'vector', url: 'https://vector.openstreetmap.org/shortbread_v1/tilejson.json'
+
+      layer(:roads, zoom: 10..13, source: :shortbread) do
+        line_width 6
+        line_color match(highway,
+                         'motorway', :blue,
+                         'trunk', :green,
+                         'primary', :red,
+                         'secondary', :orange,
+                         0x888888)
+      end
+    end.to_json
+    expect(json).to eq(<<~DOC
+      {
+        "version":8,
+        "name":"My first stylesheet",
+        "sources":{
+          "shortbread":{
+            "type":"vector",
+            "url":"https://vector.openstreetmap.org/shortbread_v1/tilejson.json"
+          }
+        },
+        "layers":[
+          {
+            "paint":{
+              "line-width":6,
+              "line-color":[
+                "match",
+                ["get","highway"],
+                "motorway",
+                "blue",
+                "trunk",
+                "green",
+                "primary",
+                "red",
+                "secondary",
+                "orange",
+                8947848
+              ]
+            },
+            "source":"shortbread",
+            "id":"roads",
+            "source-layer":"roads",
+            "type":"line",
+            "minzoom":10,
+            "maxzoom":13
+          }
+        ]
+      }
+    DOC
+    .strip)
+  end
+end

spec/spec_helper.rb

@@ -0,0 +1,101 @@
+# frozen_string_literal: true
+
+# This file was generated by the `rspec --init` command. Conventionally, all
+# specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.
+# The generated `.rspec` file contains `--require spec_helper` which will cause
+# this file to always be loaded, without a need to explicitly require it in any
+# files.
+#
+# Given that it is always loaded, you are encouraged to keep this file as
+# light-weight as possible. Requiring heavyweight dependencies from this file
+# will add to the boot time of your test suite on EVERY test run, even for an
+# individual file that may not need all of that loaded. Instead, consider making
+# a separate helper file that requires the additional dependencies and performs
+# the additional setup, and require it from the spec files that actually need
+# it.
+#
+# See https://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
+
+require 'glug'
+
+RSpec.configure do |config|
+  # rspec-expectations config goes here. You can use an alternate
+  # assertion/expectation library such as wrong or the stdlib/minitest
+  # assertions if you prefer.
+  config.expect_with :rspec do |expectations|
+    # This option will default to `true` in RSpec 4. It makes the `description`
+    # and `failure_message` of custom matchers include text for helper methods
+    # defined using `chain`, e.g.:
+    #     be_bigger_than(2).and_smaller_than(4).description
+    #     # => "be bigger than 2 and smaller than 4"
+    # ...rather than:
+    #     # => "be bigger than 2"
+    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
+  end
+
+  # rspec-mocks config goes here. You can use an alternate test double
+  # library (such as bogus or mocha) by changing the `mock_with` option here.
+  config.mock_with :rspec do |mocks|
+    # Prevents you from mocking or stubbing a method that does not exist on
+    # a real object. This is generally recommended, and will default to
+    # `true` in RSpec 4.
+    mocks.verify_partial_doubles = true
+  end
+
+  # This option will default to `:apply_to_host_groups` in RSpec 4 (and will
+  # have no way to turn it off -- the option exists only for backwards
+  # compatibility in RSpec 3). It causes shared context metadata to be
+  # inherited by the metadata hash of host groups and examples, rather than
+  # triggering implicit auto-inclusion in groups with matching metadata.
+  config.shared_context_metadata_behavior = :apply_to_host_groups
+
+  # The settings below are suggested to provide a good initial experience
+  # with RSpec, but feel free to customize to your heart's content.
+  #   # This allows you to limit a spec run to individual examples or groups
+  #   # you care about by tagging them with `:focus` metadata. When nothing
+  #   # is tagged with `:focus`, all examples get run. RSpec also provides
+  #   # aliases for `it`, `describe`, and `context` that include `:focus`
+  #   # metadata: `fit`, `fdescribe` and `fcontext`, respectively.
+  #   config.filter_run_when_matching :focus
+  #
+  #   # Allows RSpec to persist some state between runs in order to support
+  #   # the `--only-failures` and `--next-failure` CLI options. We recommend
+  #   # you configure your source control system to ignore this file.
+  #   config.example_status_persistence_file_path = "spec/examples.txt"
+  #
+  #   # Limits the available syntax to the non-monkey patched syntax that is
+  #   # recommended. For more details, see:
+  #   # https://rspec.info/features/3-12/rspec-core/configuration/zero-monkey-patching-mode/
+  #   config.disable_monkey_patching!
+  #
+  #   # This setting enables warnings. It's recommended, but in some cases may
+  #   # be too noisy due to issues in dependencies.
+  #   config.warnings = true
+  #
+  #   # Many RSpec users commonly either run the entire suite or an individual
+  #   # file, and it's useful to allow more verbose output when running an
+  #   # individual spec file.
+  #   if config.files_to_run.one?
+  #     # Use the documentation formatter for detailed output,
+  #     # unless a formatter has already been configured
+  #     # (e.g. via a command-line flag).
+  #     config.default_formatter = "doc"
+  #   end
+  #
+  #   # Print the 10 slowest examples and example groups at the
+  #   # end of the spec run, to help surface which specs are running
+  #   # particularly slow.
+  #   config.profile_examples = 10
+  #
+  #   # Run specs in random order to surface order dependencies. If you find an
+  #   # order dependency and want to debug it, you can fix the order by providing
+  #   # the seed, which is printed after each run.
+  #   #     --seed 1234
+  #   config.order = :random
+  #
+  #   # Seed global randomization in this process using the `--seed` CLI option.
+  #   # Setting this allows you to use `--seed` to deterministically reproduce
+  #   # test failures related to randomization by passing the same `--seed` value
+  #   # as the one that triggered the failure.
+  #   Kernel.srand config.seed
+end