engine: resources: pippet: Initial implementation for new resource type

The pippet resource implements faster integration of Puppet resources
in mgmt at runtime, by piping synchronization commands to a Puppet
process that keeps running alongside mgmt. This avoids huge overhead
through launching a Puppet process for each operation on a resource
that is delegated to Puppet.

engine/resources/pippet_test.go

@@ -0,0 +1,136 @@
+// Mgmt
+// Copyright (C) 2013-2019+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+// +build !root
+
+package resources
+
+import (
+	"io"
+	"testing"
+)
+
+type nullWriteCloser struct {
+}
+
+type fakePippetReceiver struct {
+	stdin  nullWriteCloser
+	stdout *io.PipeReader
+	Locked bool
+}
+
+func (obj nullWriteCloser) Write(data []byte) (int, error) {
+	return len(data), nil
+}
+
+func (obj nullWriteCloser) Close() error {
+	return nil
+}
+
+func (obj *fakePippetReceiver) LockApply() {
+	obj.Locked = true
+}
+
+func (obj *fakePippetReceiver) UnlockApply() {
+	obj.Locked = false
+}
+
+func (obj *fakePippetReceiver) InputStream() io.WriteCloser {
+	return obj.stdin
+}
+
+func (obj *fakePippetReceiver) OutputStream() io.ReadCloser {
+	return obj.stdout
+}
+
+func newFakePippetReceiver(jsonTestOutput string) *fakePippetReceiver {
+	output, input := io.Pipe()
+
+	result := &fakePippetReceiver{
+		stdout: output,
+	}
+
+	go func() {
+		// this will appear on the fake stdout
+		input.Write([]byte(jsonTestOutput))
+	}()
+
+	return result
+}
+
+var pippetTestRes = &PippetRes{
+	Type:   "notify",
+	Title:  "testmessage",
+	Params: `{msg: "This is a test"}`,
+}
+
+func TestNormalPuppetOutput(t *testing.T) {
+	r := newFakePippetReceiver(`{"resource":"Notify[test]","failed":false,"changed":true,"noop":false,"error":false,"exception":null}`)
+	changed, err := applyPippetRes(r, pippetTestRes)
+
+	if err != nil {
+		t.Errorf("normal Puppet output led to an apply error: %v", err)
+	}
+
+	if !changed {
+		t.Errorf("return values of applyPippetRes did not reflect the changed state")
+	}
+}
+
+func TestUnchangedPuppetOutput(t *testing.T) {
+	r := newFakePippetReceiver(`{"resource":"Notify[test]","failed":false,"changed":false,"noop":false,"error":false,"exception":null}`)
+	changed, err := applyPippetRes(r, pippetTestRes)
+
+	if err != nil {
+		t.Errorf("normal Puppet output led to an apply error: %v", err)
+	}
+
+	if changed {
+		t.Errorf("return values of applyPippetRes did not reflect the changed state")
+	}
+}
+
+func TestFailingPuppetOutput(t *testing.T) {
+	r := newFakePippetReceiver(`{"resource":"Notify[test]","failed":false,"changed":false,"noop":false,"error":true,"exception":"I failed!"}`)
+	_, err := applyPippetRes(r, pippetTestRes)
+
+	if err == nil {
+		t.Errorf("failing Puppet output led to an apply error: %v", err)
+	}
+}
+
+func TestEmptyPuppetOutput(t *testing.T) {
+	t.Skip("empty output will currently make the application (and the test) hang")
+}
+
+func TestPartialPuppetOutput(t *testing.T) {
+	r := newFakePippetReceiver(`{"resource":"Notify[test]","failed":false,"changed":true}`)
+	_, err := applyPippetRes(r, pippetTestRes)
+
+	if err == nil {
+		t.Errorf("partial Puppet output did not lead to an apply error")
+	}
+}
+
+func TestMalformedPuppetOutput(t *testing.T) {
+	r := newFakePippetReceiver(`oops something went wrong!!1!eleven`)
+	_, err := applyPippetRes(r, pippetTestRes)
+
+	if err == nil {
+		t.Errorf("malformed Puppet output did not lead to an apply error")
+	}
+}