[rubygems/rubygems] Introduce the Gem::CIDetector

This is based on the list in Gem::UpdateSuggestion and Bundler::Fetcher;
these have similar purposes (determining whether/what CI we're executing
in), and can benefit from being combined and updated (they're both
slightly out of date).

Noteable changes:
* We'll consider ourselves to be on a CI in more cases - if CI_NAME or
  TASKCLUSTER_ROOT_URL are set specifically, since those represent two
  cases that were either overlooked or are no longer covered by the
  existing implementation. (Or possibly TaskCluster still does provide
  RUN_ID, but failed to document it)
* We will notice/track a few additional services in ci_strings (cirrus,
  dsari, taskcluster), stop tracking 'snap' (they went under in 2017),
  and update buildbox to buildkite (they've been called that for 8
  years, and the BUILDBOX envs have been deprecated for 3).
* We'll also sort/uniq/downcase the values (all of which only matter
  because of the special case of CI_NAME).

https://github.com/rubygems/rubygems/commit/60652b942f

1 files changed, 44 insertions, 0 deletions

diff --git a/test/rubygems/test_gem_ci_detector.rb b/test/rubygems/test_gem_ci_detector.rb
new file mode 100644
index 0000000000..3caefce97d
--- /dev/null
+++ b/test/rubygems/test_gem_ci_detector.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require_relative "helper"
+require "rubygems"
+
+class TestCiDetector < Test::Unit::TestCase
+  def test_ci?
+    with_env("FOO" => "bar") { assert_equal(false, Gem::CIDetector.ci?) }
+    with_env("CI" => "true") { assert_equal(true, Gem::CIDetector.ci?) }
+    with_env("CONTINUOUS_INTEGRATION" => "1") { assert_equal(true, Gem::CIDetector.ci?) }
+    with_env("RUN_ID" => "0", "TASKCLUSTER_ROOT_URL" => "2") do
+      assert_equal(true, Gem::CIDetector.ci?)
+    end
+  end
+
+  def test_ci_strings
+    with_env("FOO" => "bar") { assert_empty(Gem::CIDetector.ci_strings) }
+    with_env("TRAVIS" => "true") { assert_equal(["travis"], Gem::CIDetector.ci_strings) }
+    with_env("CI" => "true", "CIRCLECI" => "true", "GITHUB_ACTIONS" => "true") do
+      assert_equal(["ci", "circle", "github"], Gem::CIDetector.ci_strings)
+    end
+    with_env("CI" => "true", "CI_NAME" => "MYCI") do
+      assert_equal(["ci", "myci"], Gem::CIDetector.ci_strings)
+    end
+    with_env("GITHUB_ACTIONS" => "true", "CI_NAME" => "github") do
+      assert_equal(["github"], Gem::CIDetector.ci_strings)
+    end
+    with_env("TASKCLUSTER_ROOT_URL" => "https://foo.bar", "DSARI" => "1", "CI_NAME" => "") do
+      assert_equal(["dsari", "taskcluster"], Gem::CIDetector.ci_strings)
+    end
+  end
+
+  private
+
+  def with_env(overrides, &block)
+    @orig_env = ENV.to_h
+    ENV.replace(overrides)
+    begin
+      block.call
+    ensure
+      ENV.replace(@orig_env)
+    end
+  end
+end