(maint) Add more crontab provider tests

This commit adds the following tests to the cron resource:

* A test to ensure that the crontab provider writes the crontab file of
a new user

* A test to ensure that the crontab provider fails to write the crontab
file of a nonexistent user

* A test to ensure that the crontab provider writes an originally
unauthorized user's crontab file _if_ Puppet authorizes them in the
middle of the run

These tests are part of the crontab provider's specifications and should
have been added before.

4 files changed, 255 insertions, 0 deletions

diff --git a/spec/acceptance/tests/resource/cron/should_fail_to_write_a_nonexistent_users_crontab_spec.rb b/spec/acceptance/tests/resource/cron/should_fail_to_write_a_nonexistent_users_crontab_spec.rb
new file mode 100644
index 0000000..40fbbd9
--- /dev/null
+++ b/spec/acceptance/tests/resource/cron/should_fail_to_write_a_nonexistent_users_crontab_spec.rb
@@ -0,0 +1,20 @@
+require 'spec_helper_acceptance'
+
+RSpec.context 'when Puppet attempts to write the crontab of a nonexistent user' do
+  let(:nonexistent_username) { "pl#{rand(999_999).to_i}" }
+
+  before(:each) do
+    step 'Ensure that the nonexistent user does not exist' do
+      compatible_agents.each do |agent|
+        user_absent(agent, nonexistent_username)
+      end
+    end
+  end
+
+  compatible_agents.each do |agent|
+    it "should fail on #{agent}" do
+      manifest = cron_manifest('second_entry', command: 'ls', user: nonexistent_username)
+      apply_manifest_on(agent, manifest, expect_failures: true)
+    end
+  end
+end
diff --git a/spec/acceptance/tests/resource/cron/should_write_an_originally_unauthorized_users_crontab_if_puppet_authorizes_them_spec.rb b/spec/acceptance/tests/resource/cron/should_write_an_originally_unauthorized_users_crontab_if_puppet_authorizes_them_spec.rb
new file mode 100644
index 0000000..964cc17
--- /dev/null
+++ b/spec/acceptance/tests/resource/cron/should_write_an_originally_unauthorized_users_crontab_if_puppet_authorizes_them_spec.rb
@@ -0,0 +1,111 @@
+require 'spec_helper_acceptance'
+
+RSpec.context 'when Puppet authorizes a previously unauthorized user to use crontab' do
+  class << self
+    alias_method :orig_compatible_agents, :compatible_agents
+
+    # This test is confined to AIX and Solaris agents only.
+    def compatible_agents
+      orig_compatible_agents.select do |agent|
+        agent['platform'].include?('aix') || agent['platform'].include?('solaris')
+      end
+    end
+  end
+
+  let(:username) { "pl#{rand(999_999).to_i}" }
+  let(:unauthorized_username) { "pl#{rand(999_999).to_i}" }
+
+  let(:cron_deny_path) do
+    {}
+  end
+  let(:cron_deny_original_contents) do
+    {}
+  end
+
+  before(:each) do
+    step 'Ensure that the test users exist' do
+      compatible_agents.each do |agent|
+        user_present(agent, username)
+        user_present(agent, unauthorized_username)
+      end
+    end
+
+    step 'Get the current cron.deny contents for each agent' do
+      compatible_agents.each do |agent|
+        case agent['platform']
+        when %r{aix}
+          cron_deny_path[agent] = '/var/adm/cron/cron.deny'
+        when %r{solaris}
+          cron_deny_path[agent] = '/etc/cron.d/cron.deny'
+        else
+          fail_test "Cannot figure out the path of the cron.deny file for the #{agent['platform']} platform"
+        end
+
+        cron_deny_original_contents[agent] = on(agent, "cat #{cron_deny_path[agent]}").stdout
+      end
+    end
+  end
+
+  after(:each) do
+    step 'Teardown -- Erase the test users on the agents' do
+      compatible_agents.each do |agent|
+        run_cron_on(agent, :remove, username)
+        user_absent(agent, username)
+
+        run_cron_on(agent, :remove, unauthorized_username)
+        user_absent(agent, unauthorized_username)
+      end
+    end
+
+    # It is possible for the "before" hook to raise an exception while the
+    # cron.deny contents are being computed, so only execute the next step
+    # if we've managed to compute the cron.deny contents for each agent
+    next unless cron_deny_original_contents.keys.size == compatible_agents.size
+
+    step "Teardown -- Reset each agent's cron.deny contents" do
+      compatible_agents.each do |agent|
+        apply_manifest_on(agent, file_manifest(cron_deny_path[agent], ensure: :present, content: cron_deny_original_contents[agent]))
+      end
+    end
+  end
+
+  compatible_agents.each do |agent|
+    it "should write that user's crontab on #{agent}" do
+      step 'Add the unauthorized user to the cron.deny file' do
+        on(agent, "echo #{unauthorized_username} >> #{cron_deny_path[agent]}")
+      end
+
+      step 'Verify that the unauthorized user was added to the cron.deny file' do
+        cron_deny_contents = on(agent, "cat #{cron_deny_path[agent]}").stdout
+        assert_match(%r{^#{unauthorized_username}$}, cron_deny_contents, 'Failed to add the unauthorized user to the cron.deny file')
+      end
+
+      step "Modify the unauthorized user's crontab with Puppet" do
+        # The scenario we're testing here is:
+        #   * An unrelated cron resource triggers the prefetch step, which will also
+        #   prefetch the crontab of our unauthorized user. The latter prefetch should
+        #   fail, instead returning an empty crontab file.
+        #
+        #   * Puppet authorizes our unauthorized user by removing them from the cron.deny
+        #   file.
+        #
+        #   * A cron resource linked to our (originally) unauthorized user should now be able
+        #   to write to that user's crontab file (assuming it requires the resource updating
+        #   the cron.deny file)
+        #
+        # The following manifest replicates the above scenario. Note that we test this specific
+        # scenario to ensure that the changes in PUP-9217 enforce backwards compatibility.
+        manifest = [
+          cron_manifest('first_entry', command: 'ls', user: username),
+          file_manifest(cron_deny_path[agent], ensure: :present, content: cron_deny_original_contents[agent]),
+          cron_manifest('second_entry', command: 'ls', user: unauthorized_username),
+        ].join("\n\n")
+        apply_manifest_on(agent, manifest)
+      end
+
+      step "Verify that Puppet did modify the unauthorized user's crontab" do
+        assert_matching_arrays(['* * * * * ls'], crontab_entries_of(agent, unauthorized_username), "Puppet did not modify the unauthorized user's crontab file")
+      end
+    end
+  end
+end
diff --git a/spec/acceptance/tests/resource/cron/should_write_new_users_crontab_after_puppet_creates_them_spec.rb b/spec/acceptance/tests/resource/cron/should_write_new_users_crontab_after_puppet_creates_them_spec.rb
new file mode 100644
index 0000000..12506ad
--- /dev/null
+++ b/spec/acceptance/tests/resource/cron/should_write_new_users_crontab_after_puppet_creates_them_spec.rb
@@ -0,0 +1,59 @@
+require 'spec_helper_acceptance'
+
+RSpec.context 'when Puppet creates a user in the middle of its run' do
+  let(:known_username) { "pl#{rand(999_999).to_i}" }
+  let(:new_username) { "pl#{rand(999_999).to_i}" }
+
+  before(:each) do
+    step 'Ensure that the known user exists on all of the agents' do
+      compatible_agents.each do |agent|
+        user_present(agent, known_username)
+      end
+    end
+
+    step 'Ensure that the new user does not exist on all of the agents' do
+      compatible_agents.each do |agent|
+        user_absent(agent, new_username)
+      end
+    end
+  end
+
+  after(:each) do
+    step 'Teardown -- Ensure that both users are deleted on all of the agents' do
+      compatible_agents.each do |agent|
+        run_cron_on(agent, :remove, known_username)
+        user_absent(agent, known_username)
+
+        run_cron_on(agent, :remove, new_username)
+        user_absent(agent, new_username)
+      end
+    end
+  end
+
+  compatible_agents.each do |agent|
+    it "should be able to write their crontab on #{agent}" do
+      puppet_result = nil
+      step "Create the new user, and the known + new user's crontab entries with Puppet" do
+        # Placing Cron[first_entry] before creating the new user
+        # triggers a prefetch of all the Cron resources on the
+        # system. This lets us test that the prefetch step marks
+        # the crontab of an unknown user as empty instead of marking
+        # it as a failure.
+        manifest = [
+          cron_manifest('first_entry', command: 'ls', user: known_username),
+          user_manifest(new_username, ensure: :present),
+          cron_manifest('second_entry', command: 'ls', user: new_username),
+        ].join("\n\n")
+        puppet_result = apply_manifest_on(agent, manifest)
+      end
+
+      step 'Verify that Puppet successfully evaluates a Cron resource associated with the new user' do
+        assert_match(%r{Cron.*second_entry}, puppet_result.stdout, 'Puppet fails to evaluate a Cron resource associated with a new user')
+      end
+
+      step "Verify that Puppet did create the new user's crontab file" do
+        assert_matching_arrays(['* * * * * ls'], crontab_entries_of(agent, new_username), "Puppet did not create the new user's crontab file")
+      end
+    end
+  end
+end
diff --git a/spec/spec_helper_acceptance.rb b/spec/spec_helper_acceptance.rb
index e4f0182..57c5b21 100644
--- a/spec/spec_helper_acceptance.rb
+++ b/spec/spec_helper_acceptance.rb
@@ -4,6 +4,34 @@ require 'beaker/puppet_install_helper'
 
 $LOAD_PATH << File.join(__dir__, 'acceptance/lib')
 
+# TODO: This should be added to Beaker
+def assert_matching_arrays(expected, actual, message = '')
+  assert_equal(expected.sort, actual.sort, message)
+end
+
+# TODO: Remove the wrappers to user_present
+# and user_absent if Beaker::Host's user_present
+# and user_absent functions are fixed to work with
+# Arista (EOS).
+
+def user_present(host, username)
+  case host['platform']
+  when %r{eos}
+    on(host, "useradd #{username}")
+  else
+    host.user_present(username)
+  end
+end
+
+def user_absent(host, username)
+  case host['platform']
+  when %r{eos}
+    on(host, "userdel #{username}", acceptable_exit_codes: [0, 1])
+  else
+    host.user_absent(username)
+  end
+end
+
 def beaker_opts
   { debug: true, trace: true, expect_failures: true, acceptable_exit_codes: (0...256) }
   # { expect_failures: true, acceptable_exit_codes: (0...256) }
@@ -29,6 +57,43 @@ def setup(agent, o = {})
                                 package {'cron': name=> $cron, ensure=>present, }))
 end
 
+# Returns all of the lines that correspond to crontab entries
+# on the agent. For simplicity, these are any lines that do
+# not begin with '#'.
+def crontab_entries_of(host, username)
+  crontab_contents = run_cron_on(host, :list, username).stdout.strip
+  crontab_contents.lines.map(&:chomp).reject { |line| line =~ %r{^#} }
+end
+
+def resource_manifest(resource, title, params = {})
+  params_str = params.map { |param, value|
+    # This is not quite correct for all parameter values,
+    # but it is good enough for most purposes.
+    value_str = value.to_s
+    value_str = "\"#{value_str}\"" if value.is_a?(String)
+
+    "  #{param} => #{value_str}"
+  }.join(",\n")
+
+  <<-MANIFEST
+  #{resource} { '#{title}':
+  #{params_str}
+}
+   MANIFEST
+end
+
+def file_manifest(path, params = {})
+  resource_manifest('file', path, params)
+end
+
+def cron_manifest(entry_name, params = {})
+  resource_manifest('cron', entry_name, params)
+end
+
+def user_manifest(username, params = {})
+  resource_manifest('user', username, params)
+end
+
 RSpec.configure do |c|
   c.before :suite do
     unless ENV['BEAKER_provision'] == 'no'