Start test scaffolding

 - start a test git server (thanks Stefan and Hidde!)
 - initialise it from a fixture (directory with repo contents)

This is the basics to build on.

controllers/testdata/appconfig/deploy.yaml

@@ -0,0 +1,10 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test
+spec:
+  template:
+    spec:
+      containers:
+      - name: helll
+        image: helloworld:1.0.0

controllers/update_test.go

@@ -0,0 +1,138 @@
+/*
+Copyright 2020 Michael Bridgen <mikeb@squaremobius.net>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package controllers
+
+import (
+	"context"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"time"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	corev1 "k8s.io/api/core/v1"
+	//	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	//	"k8s.io/apimachinery/pkg/types"
+	"github.com/fluxcd/source-controller/pkg/testserver"
+	"github.com/go-git/go-billy/v5/memfs"
+	"github.com/go-git/go-git/v5"
+	"github.com/go-git/go-git/v5/config"
+	//"github.com/go-git/go-git/v5/plumbing"
+	"github.com/go-git/go-git/v5/plumbing/object"
+	"github.com/go-git/go-git/v5/storage/memory"
+	//imagev1alpha1 "github.com/squaremo/image-automation-controller/api/v1alpha1"
+)
+
+const repositoryPath = "/config.git"
+
+var _ = Describe("ImageUpdateAutomation", func() {
+	var (
+		namespace *corev1.Namespace
+		gitServer *testserver.GitServer
+	)
+
+	const namespaceName = "image-update-test"
+
+	BeforeEach(func() {
+		namespace = &corev1.Namespace{}
+		namespace.Name = namespaceName
+		Expect(k8sClient.Create(context.Background(), namespace)).To(Succeed())
+
+		var err error
+		gitServer, err = testserver.NewTempGitServer()
+		Expect(err).NotTo(HaveOccurred())
+		gitServer.AutoCreate()
+	})
+
+	AfterEach(func() {
+		os.RemoveAll(gitServer.Root())
+		Expect(k8sClient.Delete(context.Background(), namespace)).To(Succeed())
+	})
+
+	It("Initialises git OK", func() {
+		Expect(gitServer.StartHTTP()).To(Succeed())
+		defer gitServer.StopHTTP()
+		Expect(initGitRepo(gitServer, "testdata/appconfig")).To(Succeed())
+	})
+})
+
+// Initialise a git server with a repo including the files in dir.
+func initGitRepo(gitServer *testserver.GitServer, fixture string) error {
+	fs := memfs.New()
+	repo, err := git.Init(memory.NewStorage(), fs)
+	if err != nil {
+		return err
+	}
+
+	if err = filepath.Walk(fixture, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return fs.MkdirAll(fs.Join(path[len(fixture):]), info.Mode())
+		}
+
+		fileBytes, err := ioutil.ReadFile(path)
+		if err != nil {
+			return err
+		}
+
+		ff, err := fs.Create(path[len(fixture):])
+		if err != nil {
+			return err
+		}
+		defer ff.Close()
+
+		_, err = ff.Write(fileBytes)
+		return err
+	}); err != nil {
+		return err
+	}
+
+	working, err := repo.Worktree()
+	if err != nil {
+		return err
+	}
+
+	_, err = working.Add(".")
+	if err != nil {
+		return err
+	}
+
+	if _, err = working.Commit("Initial revision from "+fixture, &git.CommitOptions{
+		Author: &object.Signature{
+			Name:  "Testbot",
+			Email: "test@example.com",
+			When:  time.Now(),
+		},
+	}); err != nil {
+		return err
+	}
+
+	remote, err := repo.CreateRemote(&config.RemoteConfig{
+		Name: "origin",
+		URLs: []string{gitServer.HTTPAddress() + repositoryPath},
+	})
+	if err != nil {
+		return err
+	}
+
+	return remote.Push(&git.PushOptions{
+		RefSpecs: []config.RefSpec{"refs/heads/*:refs/heads/*"},
+	})
+}

go.mod

@@ -4,6 +4,7 @@ go 1.13
 
 require (
 	github.com/fluxcd/source-controller v0.0.6
+	github.com/go-git/go-billy/v5 v5.0.0
 	github.com/go-git/go-git/v5 v5.1.0
 	github.com/go-logr/logr v0.1.0
 	github.com/google/go-containerregistry v0.1.1
@@ -16,3 +17,6 @@ require (
 	sigs.k8s.io/controller-runtime v0.6.1
 	sigs.k8s.io/kustomize/kyaml v0.4.1
 )
+
+//  https://github.com/sosedoff/gitkit/pull/21
+replace github.com/sosedoff/gitkit => github.com/hiddeco/gitkit v0.2.1-0.20200422093229-4355fec70348