Add initial implementation of Module#const_set_p.

Author: epaew

lib/const_set_p.rb

@@ -1,8 +1,4 @@
 # frozen_string_literal: true
 
+require_relative "const_set_p/core_ext"
 require_relative "const_set_p/version"
-
-module ConstSetP
-  class Error < StandardError; end
-  # Your code goes here...
-end

lib/const_set_p/core_ext.rb

@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+require_relative "core_ext/module"

lib/const_set_p/core_ext/module.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+class Module
+  def const_set_p(name, value)
+    first, rest = name.to_s.split("::", 2)
+    return const_set(first, value) unless rest
+
+    submod =
+      if const_defined?(first, false)
+        const_get(first, false)
+      else
+        const_set(first, Module.new)
+      end
+    raise NameError, "#{self.name}::#{first} is not a Module or Class" unless submod.is_a?(Module)
+
+    submod.const_set_p(rest, value)
+  end
+end

sig/const_set_p.rbs

@@ -1,4 +1,3 @@
 module ConstSetP
   VERSION: String
-  # See the writing guide of rbs: https://github.com/ruby/rbs#guides
 end

sig/module.rbs

@@ -0,0 +1,3 @@
+class Module
+  def const_set_p: (interned name, untyped value) -> untyped
+end

spec/const_set_p/core_ext/module_spec.rb

@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+require "securerandom"
+
+RSpec.describe Module do
+  describe "#const_set_p" do
+    subject { mod.const_set_p(name, value) }
+
+    let(:mod) do
+      Module.new do
+        const_set(:C, Class.new)
+        const_set(:S, "string")
+      end
+    end
+    let(:value) { SecureRandom.uuid }
+
+    context 'when the name does not contain "::"' do
+      let(:name) { "N" }
+
+      it "defines M::N and it returns value" do
+        subject
+        expect(mod::N).to eq value
+      end
+    end
+
+    context 'when the name contains "::"' do
+      context "when the name does not contain the name of a pre-defined constant" do
+        let(:name) { "N::O" }
+
+        it "defines M::N and M::N::O and it returns Module" do
+          subject
+          expect(mod::N).to be_a Module
+        end
+
+        it "defines M::N::O and it returns value" do
+          subject
+          expect(mod::N::O).to eq value
+        end
+      end
+
+      context "when the name contains the name of a pre-defined constant" do
+        context "when the type of constant is a Class or Module" do
+          let(:name) { "C::D" }
+
+          it "does not replace M::C" do
+            expect { subject }.not_to(change { mod::C })
+          end
+
+          it "defines M::C::D and it returns value" do
+            subject
+            expect(mod::C::D).to eq value
+          end
+        end
+
+        context "when the type of constant is not a Class or Module" do
+          let(:name) { "S::T" }
+
+          it { expect { subject }.to raise_error(NameError) }
+        end
+      end
+    end
+  end
+end

spec/spec_helper.rb

@@ -1,3 +1,5 @@
+# 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
@@ -13,6 +15,25 @@
 # it.
 #
 # See https://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
+
+require "simplecov"
+require "simplecov-console"
+require "simplecov_json_formatter"
+
+SimpleCov.start do
+  add_filter "/spec/"
+  enable_coverage :branch
+  formatter SimpleCov::Formatter::MultiFormatter.new(
+    [
+      SimpleCov::Formatter::JSONFormatter, # for codeclimate
+      SimpleCov::Formatter::Console        # for stdout
+    ]
+  )
+end
+
+require "bundler/setup"
+require "const_set_p"
+
 RSpec.configure do |config|
   # rspec-expectations config goes here. You can use an alternate
   # assertion/expectation library such as wrong or the stdlib/minitest
@@ -44,9 +65,6 @@
   # 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.
-=begin
   # 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
@@ -94,5 +112,4 @@
   # test failures related to randomization by passing the same `--seed` value
   # as the one that triggered the failure.
   Kernel.srand config.seed
-=end
 end