Introduce PathBuilder

src/go/testsupportfs/dir_fixture.go

@@ -32,6 +32,7 @@ type dirFixtureState interface {
 	BasePath() (string, error)
 	Create() (dirFixtureState, error)
 	Destroy() (dirFixtureState, error)
+	PathBuilder() (*PathBuilder, error)
 }
 
 /* Use */
@@ -40,3 +41,8 @@ type dirFixtureState interface {
 func (fixture *DirFixture) BasePath() (string, error) {
 	return fixture.state.BasePath()
 }
+
+// Get something to build paths inside of the test directory, provided it has been created.
+func (fixture *DirFixture) PathBuilder() (*PathBuilder, error) {
+	return fixture.state.PathBuilder()
+}

src/go/testsupportfs/dir_fixture_down.go

@@ -27,3 +27,7 @@ func (down *dirFixtureDown) Create() (dirFixtureState, error) {
 func (down *dirFixtureDown) Destroy() (dirFixtureState, error) {
 	return down, nil
 }
+
+func (down *dirFixtureDown) PathBuilder() (*PathBuilder, error) {
+	return nil, fmt.Errorf("test directory starting with <%s> not created yet", down.prefix)
+}

src/go/testsupportfs/dir_fixture_up.go

@@ -24,3 +24,7 @@ func (up *dirFixtureUp) Destroy() (dirFixtureState, error) {
 
 	return &dirFixtureDown{prefix: up.createdWithPrefix}, nil
 }
+
+func (up *dirFixtureUp) PathBuilder() (*PathBuilder, error) {
+	return &PathBuilder{basePath: up.dirPath}, nil
+}

src/go/testsupportfs/path_builder.go

@@ -0,0 +1,10 @@
+package testsupportfs
+
+// Builds paths with certain properties inside of an existing base directory.
+type PathBuilder struct {
+	basePath string
+}
+
+func (builder *PathBuilder) AsAbsolute() string {
+	return builder.basePath
+}

src/go/userepository/register_local_repositories_command_test.go

@@ -15,9 +15,17 @@ import (
 
 var _ = Describe("RegisterLocalRepositoriesCommand", func() {
 	var (
-		dirFixture *testsupportfs.DirFixture
-		source     *mock.RepositorySource
-		subject    *userepository.RegisterLocalRepositoriesCommand
+		subject *userepository.RegisterLocalRepositoriesCommand
+		runV    = func(paths ...string) error {
+			return subject.Run(paths)
+		}
+	)
+
+	var source *mock.RepositorySource
+
+	var (
+		dirFixture  *testsupportfs.DirFixture
+		pathBuilder *testsupportfs.PathBuilder
 	)
 
 	var validPaths = func() []string {
@@ -28,18 +36,20 @@ var _ = Describe("RegisterLocalRepositoriesCommand", func() {
 		dirFixture = testsupportfs.NewDirFixture("RegisterLocalRepositoriesCommand")
 		Expect(dirFixture.Setup()).To(Succeed())
 		DeferCleanup(dirFixture.Teardown)
+		pathBuilder = expect.NoError(dirFixture.PathBuilder())
 
 		source = mock.NewRepositorySource()
 		factory := use.NewCommandFactory().WithRepositorySource(source)
 		subject = expect.NoError(factory.NewRegisterLocalRepositories())
 	})
 
 	Describe("#Run", func() {
-		It("accepts absolute and relative paths", func() {
-			Expect(subject.Run([]string{
-				"/home/me/absolute",
-				"../git/relative",
-			})).To(Succeed())
+		It("accepts absolute paths", func() {
+			Expect(runV(pathBuilder.AsAbsolute())).To(Succeed())
+		})
+
+		It("accepts relative paths", func() {
+			Expect(subject.Run([]string{"../git/relative"})).To(Succeed())
 		})
 
 		It("adds local repositories to the source, for the given paths", func() {