Fixed few gitlab:check tasks that were failing with exception

changelogs/unreleased/38280-undefined-run_command-when-running-rake-gitlab-check.yml

+---
+title: Some checks in `rake gitlab:check` were failling with 'undefined method `run_command`'
+merge_request: 14469
+author:
+type: fixed

lib/system_check/app/git_version_check.rb

@@ -9,7 +9,7 @@ module SystemCheck
       end
 
       def self.current_version
-        @current_version ||= Gitlab::VersionInfo.parse(run_command(%W(#{Gitlab.config.git.bin_path} --version)))
+        @current_version ||= Gitlab::VersionInfo.parse(Gitlab::TaskHelpers.run_command(%W(#{Gitlab.config.git.bin_path} --version)))
       end
 
       def check?

lib/system_check/app/ruby_version_check.rb

@@ -9,7 +9,7 @@ module SystemCheck
       end
 
       def self.current_version
-        @current_version ||= Gitlab::VersionInfo.parse(run_command(%w(ruby --version)))
+        @current_version ||= Gitlab::VersionInfo.parse(Gitlab::TaskHelpers.run_command(%w(ruby --version)))
       end
 
       def check?

spec/lib/system_check/base_check_spec.rb

+require 'spec_helper'
+
+describe SystemCheck::BaseCheck do
+  context 'helpers on instance level' do
+    it 'responds to SystemCheck::Helpers methods' do
+      expect(subject).to respond_to :fix_and_rerun, :for_more_information, :see_installation_guide_section,
+        :finished_checking, :start_checking, :try_fixing_it, :sanitized_message, :should_sanitize?, :omnibus_gitlab?,
+        :sudo_gitlab
+    end
+
+    it 'responds to Gitlab::TaskHelpers methods' do
+      expect(subject).to respond_to :ask_to_continue, :os_name, :prompt, :run_and_match, :run_command,
+        :run_command!, :uid_for, :gid_for, :gitlab_user, :gitlab_user?, :warn_user_is_not_gitlab, :all_repos,
+        :repository_storage_paths_args, :user_home, :checkout_or_clone_version, :clone_repo, :checkout_version
+    end
+  end
+end

spec/tasks/gitlab/task_helpers_spec.rb

@@ -75,4 +75,24 @@ describe Gitlab::TaskHelpers do
       subject.checkout_version(tag, clone_path)
     end
   end
+
+  describe '#run_command' do
+    it 'runs command and return the output' do
+      expect(subject.run_command(%w(echo it works!))).to eq("it works!\n")
+    end
+
+    it 'returns empty string when command doesnt exist' do
+      expect(subject.run_command(%w(nonexistentcommand with arguments))).to eq('')
+    end
+  end
+
+  describe '#run_command!' do
+    it 'runs command and return the output' do
+      expect(subject.run_command!(%w(echo it works!))).to eq("it works!\n")
+    end
+
+    it 'returns and exception when command exit with non zero code' do
+      expect { subject.run_command!(['bash', '-c', 'exit 1']) }.to raise_error Gitlab::TaskFailedError
+    end
+  end
 end