test, integration: Add an integration test framework

This adds an initial implementation of an integration test framework for
writing more complicated tests. In particular this also makes some small
additions to the mgmt core so that testing is easier.

integration/patterns.go

@@ -0,0 +1,79 @@
+// Mgmt
+// Copyright (C) 2013-2018+ 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/>.
+
+package integration
+
+import (
+	"context"
+	"time"
+
+	errwrap "github.com/pkg/errors"
+)
+
+// SimpleDeployLang is a helper method that takes a struct and runs a sequence
+// of methods on it. This particular helper starts up an instance, deploys some
+// code, and then shuts down. Both after initially starting up, and after
+// deploy, it waits for the instance to converge before running the next step.
+func (obj *Instance) SimpleDeployLang(code string) error {
+	if err := obj.Init(); err != nil {
+		return errwrap.Wrapf(err, "could not init instance")
+	}
+	defer obj.Close() // clean up working directories
+
+	// run the program
+	if err := obj.Run(nil); err != nil {
+		return errwrap.Wrapf(err, "mgmt could not start")
+	}
+	defer obj.Kill() // do a kill -9
+
+	// wait for an internal converge signal as a baseline
+	{
+		ctx, cancel := context.WithTimeout(context.Background(), longTimeout*time.Second)
+		defer cancel()
+		if err := obj.Wait(ctx); err != nil { // wait to get a converged signal
+			return errwrap.Wrapf(err, "mgmt wait failed") // timeout expired
+		}
+	}
+
+	// push a deploy
+	if err := obj.DeployLang(code); err != nil {
+		return errwrap.Wrapf(err, "mgmt could not deploy")
+	}
+
+	// wait for an internal converge signal
+	{
+		ctx, cancel := context.WithTimeout(context.Background(), longTimeout*time.Second)
+		defer cancel()
+		if err := obj.Wait(ctx); err != nil { // wait to get a converged signal
+			return errwrap.Wrapf(err, "mgmt wait failed") // timeout expired
+		}
+	}
+
+	// press ^C
+	{
+		ctx, cancel := context.WithTimeout(context.Background(), longTimeout*time.Second)
+		defer cancel()
+		if err := obj.Quit(ctx); err != nil {
+			if err == context.DeadlineExceeded {
+				return errwrap.Wrapf(err, "mgmt blocked on exit")
+			}
+			return errwrap.Wrapf(err, "mgmt exited with error")
+		}
+	}
+
+	return nil
+}