diff --git a/pkg/collection/imagetxt/imagetxt.go b/pkg/collection/imagetxt/imagetxt.go
index ae4b113..b6b34d5 100644
--- a/pkg/collection/imagetxt/imagetxt.go
+++ b/pkg/collection/imagetxt/imagetxt.go
@@ -22,8 +22,8 @@ type ImageTxt struct {
 	IncludeSources map[string]bool
 	ExcludeSources map[string]bool
 
-	getter   local.Opener
 	lock     *sync.Mutex
+	getter   local.Opener
 	computed bool
 	contents map[name.Reference]artifact.OCI
 }
@@ -34,23 +34,6 @@ type Option interface {
 	Apply(*ImageTxt) error
 }
 
-type withRef string
-
-func (o withRef) Apply(it *ImageTxt) error {
-	ref := string(o)
-
-	if strings.HasPrefix(ref, "http") || strings.HasPrefix(ref, "https") {
-		it.getter = local.RemoteOpener(ref)
-	} else {
-		it.getter = local.LocalOpener(ref)
-	}
-	return nil
-}
-
-func WithRef(ref string) Option {
-	return withRef(ref)
-}
-
 type withIncludeSources []string
 
 func (o withIncludeSources) Apply(it *ImageTxt) error {
@@ -83,11 +66,19 @@ func WithExcludeSources(exclude ...string) Option {
 	return withExcludeSources(exclude)
 }
 
-func New(opts ...Option) (*ImageTxt, error) {
+func New(ref string, opts ...Option) (*ImageTxt, error) {
 	it := &ImageTxt{
+		Ref: ref,
+
 		lock: &sync.Mutex{},
 	}
 
+	if strings.HasPrefix(ref, "http") || strings.HasPrefix(ref, "https") {
+		it.getter = local.RemoteOpener(ref)
+	} else {
+		it.getter = local.LocalOpener(ref)
+	}
+
 	for i, o := range opts {
 		if err := o.Apply(it); err != nil {
 			return nil, fmt.Errorf("invalid option %d: %v", i, err)
@@ -139,7 +130,7 @@ func (it *ImageTxt) compute() error {
 	}
 
 	var pullAll bool
-	var targetSources map[string]bool
+	targetSources := make(map[string]bool)
 
 	if len(foundSources) == 0 || (len(it.IncludeSources) == 0 && len(it.ExcludeSources) == 0) {
 		// pull all found images
diff --git a/pkg/collection/imagetxt/imagetxt_test.go b/pkg/collection/imagetxt/imagetxt_test.go
new file mode 100644
index 0000000..556a85a
--- /dev/null
+++ b/pkg/collection/imagetxt/imagetxt_test.go
@@ -0,0 +1,216 @@
+package imagetxt
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"testing"
+
+	"github.com/google/go-containerregistry/pkg/name"
+
+	artifacts "github.com/rancherfederal/hauler/pkg/artifact"
+	"github.com/rancherfederal/hauler/pkg/content/image"
+)
+
+var (
+	ErrInvalidRef     = errors.New("invalid reference")
+	ErrRefNotFound    = errors.New("ref not found")
+	ErrRefNotImage    = errors.New("ref is not image")
+	ErrExtraRefsFound = errors.New("extra refs found in contents")
+)
+
+var (
+	testServer *httptest.Server
+)
+
+func TestMain(m *testing.M) {
+	setup()
+	code := m.Run()
+	teardown()
+	os.Exit(code)
+}
+
+func setup() {
+	dir := http.Dir("./testdata/http/")
+	h := http.FileServer(dir)
+	testServer = httptest.NewServer(h)
+}
+
+func teardown() {
+	if testServer != nil {
+		testServer.Close()
+	}
+}
+
+type failKind string
+
+const (
+	failKindNew      = failKind("New")
+	failKindContents = failKind("Contents")
+)
+
+func checkError(checkedFailKind failKind) func(*testing.T, error, bool, failKind) {
+	return func(cet *testing.T, err error, testShouldFail bool, testFailKind failKind) {
+		if err != nil {
+			// if error should not have happened at all OR error should have happened
+			// at a different point, test failed
+			if !testShouldFail || testFailKind != checkedFailKind {
+				cet.Fatalf("unexpected error at %s: %v", checkedFailKind, err)
+			}
+			// test should fail at this point, test passed
+			return
+		}
+		// if no error occurred but error should have happened at this point, test
+		// failed
+		if testShouldFail && testFailKind == checkedFailKind {
+			cet.Fatalf("unexpected nil error at %s", checkedFailKind)
+		}
+	}
+}
+
+func TestImageTxtCollection(t *testing.T) {
+	type testEntry struct {
+		Name           string
+		Ref            string
+		IncludeSources []string
+		ExcludeSources []string
+		ExpectedImages []string
+		ShouldFail     bool
+		FailKind       failKind
+	}
+	tt := []testEntry{
+		{
+			Name: "http ref basic",
+			Ref:  fmt.Sprintf("%s/images-http.txt", testServer.URL),
+			ExpectedImages: []string{
+				"busybox",
+				"nginx:1.19",
+				"rancher/hyperkube:v1.21.7-rancher1",
+				"docker.io/rancher/klipper-lb:v0.3.4",
+				"quay.io/jetstack/cert-manager-controller:v1.6.1",
+			},
+		},
+		{
+			Name: "http ref sources format pull all",
+			Ref:  fmt.Sprintf("%s/images-src-http.txt", testServer.URL),
+			ExpectedImages: []string{
+				"busybox",
+				"nginx:1.19",
+				"rancher/hyperkube:v1.21.7-rancher1",
+				"docker.io/rancher/klipper-lb:v0.3.4",
+				"quay.io/jetstack/cert-manager-controller:v1.6.1",
+			},
+		},
+		{
+			Name: "http ref sources format include sources A",
+			Ref:  fmt.Sprintf("%s/images-src-http.txt", testServer.URL),
+			IncludeSources: []string{
+				"core", "rke",
+			},
+			ExpectedImages: []string{
+				"busybox",
+				"nginx:1.19",
+				"rancher/hyperkube:v1.21.7-rancher1",
+			},
+		},
+		{
+			Name: "http ref sources format include sources B",
+			Ref:  fmt.Sprintf("%s/images-src-http.txt", testServer.URL),
+			IncludeSources: []string{
+				"nginx", "rancher", "cert-manager",
+			},
+			ExpectedImages: []string{
+				"nginx:1.19",
+				"rancher/hyperkube:v1.21.7-rancher1",
+				"docker.io/rancher/klipper-lb:v0.3.4",
+				"quay.io/jetstack/cert-manager-controller:v1.6.1",
+			},
+		},
+		{
+			Name: "http ref sources format exclude sources A",
+			Ref:  fmt.Sprintf("%s/images-src-http.txt", testServer.URL),
+			ExcludeSources: []string{
+				"cert-manager",
+			},
+			ExpectedImages: []string{
+				"busybox",
+				"nginx:1.19",
+				"rancher/hyperkube:v1.21.7-rancher1",
+				"docker.io/rancher/klipper-lb:v0.3.4",
+			},
+		},
+		{
+			Name: "http ref sources format exclude sources B",
+			Ref:  fmt.Sprintf("%s/images-src-http.txt", testServer.URL),
+			ExcludeSources: []string{
+				"core",
+			},
+			ExpectedImages: []string{
+				"nginx:1.19",
+				"rancher/hyperkube:v1.21.7-rancher1",
+				"docker.io/rancher/klipper-lb:v0.3.4",
+				"quay.io/jetstack/cert-manager-controller:v1.6.1",
+			},
+		},
+		{
+			Name: "local file ref",
+			Ref:  "./testdata/images-file.txt",
+			ExpectedImages: []string{
+				"busybox",
+				"nginx:1.19",
+				"rancher/hyperkube:v1.21.7-rancher1",
+				"docker.io/rancher/klipper-lb:v0.3.4",
+				"quay.io/jetstack/cert-manager-controller:v1.6.1",
+			},
+		},
+	}
+
+	checkErrorNew := checkError(failKindNew)
+	checkErrorContents := checkError(failKindContents)
+
+	for _, curTest := range tt {
+		t.Run(curTest.Name, func(innerT *testing.T) {
+			curImageTxt, err := New(curTest.Ref,
+				WithIncludeSources(curTest.IncludeSources...),
+				WithExcludeSources(curTest.ExcludeSources...),
+			)
+			checkErrorNew(innerT, err, curTest.ShouldFail, curTest.FailKind)
+
+			ociContents, err := curImageTxt.Contents()
+			checkErrorContents(innerT, err, curTest.ShouldFail, curTest.FailKind)
+
+			if err := checkImages(ociContents, curTest.ExpectedImages); err != nil {
+				innerT.Fatal(err)
+			}
+		})
+	}
+}
+
+func checkImages(content map[name.Reference]artifacts.OCI, refs []string) error {
+	contentCopy := make(map[name.Reference]artifacts.OCI, len(content))
+	for k, v := range content {
+		contentCopy[k] = v
+	}
+	for _, ref := range refs {
+		nameRef, err := name.ParseReference(ref)
+		if err != nil {
+			return fmt.Errorf("ref %s: %w", ref, ErrInvalidRef)
+		}
+		target, ok := content[nameRef]
+		if !ok {
+			return fmt.Errorf("ref %s: %w", ref, ErrRefNotFound)
+		}
+		if _, ok := target.(*image.Image); !ok {
+			return fmt.Errorf("got underlying type %T: %w", target, ErrRefNotImage)
+		}
+		delete(contentCopy, nameRef)
+	}
+
+	if len(contentCopy) != 0 {
+		return ErrExtraRefsFound
+	}
+
+	return nil
+}
diff --git a/pkg/collection/imagetxt/testdata/http/images-http.txt b/pkg/collection/imagetxt/testdata/http/images-http.txt
new file mode 100644
index 0000000..0ae5fa8
--- /dev/null
+++ b/pkg/collection/imagetxt/testdata/http/images-http.txt
@@ -0,0 +1,5 @@
+busybox
+nginx:1.19
+rancher/hyperkube:v1.21.7-rancher1
+docker.io/rancher/klipper-lb:v0.3.4
+quay.io/jetstack/cert-manager-controller:v1.6.1
diff --git a/pkg/collection/imagetxt/testdata/http/images-src-http.txt b/pkg/collection/imagetxt/testdata/http/images-src-http.txt
new file mode 100644
index 0000000..013abe6
--- /dev/null
+++ b/pkg/collection/imagetxt/testdata/http/images-src-http.txt
@@ -0,0 +1,5 @@
+busybox core
+nginx:1.19 core,nginx
+rancher/hyperkube:v1.21.7-rancher1 rancher,rke
+docker.io/rancher/klipper-lb:v0.3.4 rancher,k3s
+quay.io/jetstack/cert-manager-controller:v1.6.1 cert-manager
diff --git a/pkg/collection/imagetxt/testdata/images-file.txt b/pkg/collection/imagetxt/testdata/images-file.txt
new file mode 100644
index 0000000..0ae5fa8
--- /dev/null
+++ b/pkg/collection/imagetxt/testdata/images-file.txt
@@ -0,0 +1,5 @@
+busybox
+nginx:1.19
+rancher/hyperkube:v1.21.7-rancher1
+docker.io/rancher/klipper-lb:v0.3.4
+quay.io/jetstack/cert-manager-controller:v1.6.1
diff --git a/pkg/content/image/image.go b/pkg/content/image/image.go
index 4ac8ab8..d7c70a9 100644
--- a/pkg/content/image/image.go
+++ b/pkg/content/image/image.go
@@ -8,9 +8,9 @@ import (
 	"github.com/rancherfederal/hauler/pkg/artifact"
 )
 
-var _ artifact.OCI = (*image)(nil)
+var _ artifact.OCI = (*Image)(nil)
 
-func (i *image) MediaType() string {
+func (i *Image) MediaType() string {
 	mt, err := i.Image.MediaType()
 	if err != nil {
 		return ""
@@ -18,15 +18,15 @@ func (i *image) MediaType() string {
 	return string(mt)
 }
 
-func (i *image) RawConfig() ([]byte, error) {
+func (i *Image) RawConfig() ([]byte, error) {
 	return i.RawConfigFile()
 }
 
-type image struct {
+type Image struct {
 	gv1.Image
 }
 
-func NewImage(ref string) (*image, error) {
+func NewImage(ref string) (*Image, error) {
 	r, err := name.ParseReference(ref)
 	if err != nil {
 		return nil, err
@@ -37,7 +37,7 @@ func NewImage(ref string) (*image, error) {
 		return nil, err
 	}
 
-	return &image{
+	return &Image{
 		Image: img,
 	}, nil
 }