Implemented a Ruby class to access GitVersion's information

Author: agross

GitVersionExe/GemAssets/lib/git_version.rb

@@ -0,0 +1,49 @@
+require 'json'
+require 'open3'
+
+class GitVersion
+  attr_reader :args
+  attr_accessor :gitversion_exe
+
+  def initialize(args = [])
+    @args = args
+  end
+
+  def method_missing(symbol, *args)
+    keys = [symbol.to_s, pascal_case(symbol.to_s)]
+
+    found_key = keys.find { |key| json.has_key?(key) }
+    return json[found_key] if found_key
+
+    super
+  end
+
+  def json
+    @json ||= run_gitversion
+  end
+
+  def gitversion_exe
+    @gitversion_exe ||= File.join(File.dirname(__FILE__), '../bin/GitVersion.exe')
+  end
+
+  private
+  def run_gitversion
+    cmd = [gitversion_exe]
+    cmd << args
+    cmd = cmd.flatten.reject(&:nil?)
+
+    stdout_and_stderr, status = Open3.capture2e(*cmd)
+
+    raise StandardError.new("Failed running #{cmd.join(' ')}, #{status}. We received the following output:\n#{stdout_and_stderr}") unless status.success?
+
+    JSON.parse(stdout_and_stderr)
+  end
+
+  def pascal_case(str)
+    str
+      .to_s
+      .split('_')
+      .inject([]) { |buffer, e| buffer.push(e.capitalize) }
+      .join
+  end
+end

GitVersionExe/GemAssets/spec/lib/git_version_spec.rb

@@ -0,0 +1,83 @@
+require 'git_version'
+
+describe GitVersion do
+  describe 'defaults' do
+    its(:gitversion_exe) { should match(%r|\.\./bin/GitVersion.exe$|) }
+    its(:args) { should be_empty }
+  end
+
+  describe 'GitVersion.exe invocation' do
+    before {
+      allow(Open3).to receive(:capture2e).and_return(gitversion_exe_return)
+    }
+
+    let(:gitversion_exe_return) { ['{ "Sha": 1234 }', OpenStruct.new(success?: true)] }
+
+    describe 'cached results' do
+      context 'accessing multiple properties' do
+        it 'should run GitVersion.exe only once' do
+          subject.sha
+          subject.sha
+
+          expect(Open3).to have_received(:capture2e).once
+        end
+      end
+    end
+
+    describe 'arguments' do
+      subject { described_class.new(args) }
+
+      let(:args) { %w(some additional args) }
+
+      it 'should pass args to the executable' do
+        subject.sha
+
+        expect(Open3).to have_received(:capture2e).with(*([subject.gitversion_exe] + args))
+      end
+    end
+
+    context 'GitVersion.exe fails' do
+      let(:gitversion_exe_return) { ['some error output', OpenStruct.new(success?: false)] }
+
+      it 'should fail' do
+        expect { subject.it_does_not_matter }.to raise_error(StandardError, /Failed running.*some error output/m)
+      end
+    end
+  end
+
+  describe 'after the executable has been built' do
+    before {
+      subject.gitversion_exe = File.expand_path('../../GemBuild/bin/GitVersion.exe')
+    }
+
+    its(:json) { should_not be_nil }
+    its(:sha) { should match(/[0-9 a-f]{40}/) }
+  end
+
+  describe 'accessing properties' do
+    before {
+      allow(subject).to receive(:json).and_return(json)
+    }
+
+    let(:json) { { 'InformationalVersion' => 'blah' } }
+
+    it 'should translate snake case to pascal case' do
+      expect(subject.informational_version).to eq('blah')
+    end
+
+    it 'should support pascal case' do
+      pascal = subject.InformationalVersion
+      snake = subject.informational_version
+
+      expect(pascal).to eq(snake)
+    end
+
+    context 'with nil value' do
+      let(:json) { { 'is_nil' => nil } }
+
+      it 'should yield nil' do
+        expect(subject.is_nil).to be_nil
+      end
+    end
+  end
+end

GitVersionExe/GemAssets/spec/spec_helper.rb

@@ -0,0 +1,7 @@
+require 'rspec/its'
+
+RSpec.configure do |config|
+  config.expect_with :rspec do |c|
+    c.syntax = :expect
+  end
+end