add Utils::Git.root method that returns root of the current git repos…

…itory

lib/datadog/ci/utils/git.rb

@@ -19,6 +19,12 @@ def self.is_git_tag?(ref)
           !ref.nil? && ref.include?("tags/")
         end
 
+        def self.root
+          return @@root if defined?(@@root)
+
+          @@root = exec_git_command("git rev-parse --show-toplevel")
+        end
+
         def self.exec_git_command(cmd)
           out, status = Open3.capture2e(cmd)
 

sig/datadog/ci/utils/git.rbs

@@ -2,6 +2,8 @@ module Datadog
   module CI
     module Utils
       module Git
+        @@root: String?
+
         def self?.normalize_ref: (untyped name) -> (nil | untyped)
 
         def self?.is_git_tag?: (untyped ref) -> untyped

spec/datadog/ci/utils/git_spec.rb

@@ -46,4 +46,22 @@
       it { is_expected.to be_truthy }
     end
   end
+
+  describe ".root" do
+    subject { described_class.root }
+
+    it { is_expected.to eq(Dir.pwd) }
+
+    context "caches the result" do
+      before do
+        expect(Open3).to receive(:capture2e).never
+      end
+
+      it "returns the same result" do
+        2.times do
+          expect(described_class.root).to eq(Dir.pwd)
+        end
+      end
+    end
+  end
 end