diff --git a/cmd/gen-manifests/main.go b/cmd/gen-manifests/main.go
index 24a6d27939..64e717afd3 100644
--- a/cmd/gen-manifests/main.go
+++ b/cmd/gen-manifests/main.go
@@ -338,16 +338,7 @@ func mockResolveCommits(commitSources map[string][]ostree.SourceSpec) map[string
 	for name, commitSources := range commitSources {
 		commitSpecs := make([]ostree.CommitSpec, len(commitSources))
 		for idx, commitSource := range commitSources {
-			checksum := fmt.Sprintf("%x", sha256.Sum256([]byte(commitSource.URL+commitSource.Ref)))
-			spec := ostree.CommitSpec{
-				Ref:      commitSource.Ref,
-				URL:      commitSource.URL,
-				Checksum: checksum,
-			}
-			if commitSource.RHSM {
-				spec.Secrets = "org.osbuild.rhsm.consumer"
-			}
-			commitSpecs[idx] = spec
+			commitSpecs[idx] = cmdutil.MockOSTreeResolve(commitSource)
 		}
 		commits[name] = commitSpecs
 	}
diff --git a/cmd/otk-resolve-ostree-commit/export_test.go b/cmd/otk-resolve-ostree-commit/export_test.go
index 77c5f1a937..2de3e0d412 100644
--- a/cmd/otk-resolve-ostree-commit/export_test.go
+++ b/cmd/otk-resolve-ostree-commit/export_test.go
@@ -3,3 +3,16 @@ package main
 var (
 	Run = run
 )
+
+func MockEnvLookup() (restore func()) {
+	saved := osLookupEnv
+	osLookupEnv = func(key string) (string, bool) {
+		if key == "OTK_UNDER_TEST" {
+			return "1", true
+		}
+		return "", false
+	}
+	return func() {
+		osLookupEnv = saved
+	}
+}
diff --git a/cmd/otk-resolve-ostree-commit/main.go b/cmd/otk-resolve-ostree-commit/main.go
index e874443a37..ee051ce9a3 100644
--- a/cmd/otk-resolve-ostree-commit/main.go
+++ b/cmd/otk-resolve-ostree-commit/main.go
@@ -6,6 +6,7 @@ import (
 	"io"
 	"os"
 
+	"github.com/osbuild/images/internal/cmdutil"
 	"github.com/osbuild/images/pkg/ostree"
 )
 
@@ -48,6 +49,14 @@ type OutputConst struct {
 	Checksum string `json:"checksum"`
 }
 
+// for mocking in testing
+var osLookupEnv = os.LookupEnv
+
+func underTest() bool {
+	testVar, found := osLookupEnv("OTK_UNDER_TEST")
+	return found && testVar == "1"
+}
+
 func run(r io.Reader, w io.Writer) error {
 	var inputTree Tree
 	if err := json.NewDecoder(r).Decode(&inputTree); err != nil {
@@ -55,9 +64,16 @@ func run(r io.Reader, w io.Writer) error {
 	}
 
 	sourceSpec := ostree.SourceSpec(inputTree.Tree)
-	commitSpec, err := ostree.Resolve(sourceSpec)
-	if err != nil {
-		return fmt.Errorf("failed to resolve ostree commit: %w", err)
+
+	var commitSpec ostree.CommitSpec
+	if !underTest() {
+		var err error
+		commitSpec, err = ostree.Resolve(sourceSpec)
+		if err != nil {
+			return fmt.Errorf("failed to resolve ostree commit: %w", err)
+		}
+	} else {
+		commitSpec = cmdutil.MockOSTreeResolve(sourceSpec)
 	}
 
 	output := map[string]Output{
diff --git a/cmd/otk-resolve-ostree-commit/main_test.go b/cmd/otk-resolve-ostree-commit/main_test.go
index 841ff5622f..2139dcfb43 100644
--- a/cmd/otk-resolve-ostree-commit/main_test.go
+++ b/cmd/otk-resolve-ostree-commit/main_test.go
@@ -191,3 +191,35 @@ func TestResolverErrors(t *testing.T) {
 		})
 	}
 }
+
+func TestMockResolve(t *testing.T) {
+	restore := resolver.MockEnvLookup()
+	defer restore()
+
+	assert := assert.New(t)
+
+	inputReq := `
+{
+  "tree": {
+    "ref": "otk/ostree/test",
+    "url": "https://ostree.example.org/repo"
+  }
+}
+`
+	expOutput := `{
+  "tree": {
+    "const": {
+      "ref": "otk/ostree/test",
+      "url": "https://ostree.example.org/repo",
+      "checksum": "5c1c0655481926623eca85109dd4017c8dba320ea1473c42b43005db6d900a60"
+    }
+  }
+}
+`
+	input := bytes.NewBuffer([]byte(inputReq))
+	output := &bytes.Buffer{}
+
+	assert.NoError(resolver.Run(input, output))
+
+	assert.Equal(expOutput, output.String())
+}
diff --git a/internal/cmdutil/mock.go b/internal/cmdutil/mock.go
new file mode 100644
index 0000000000..17f3993f28
--- /dev/null
+++ b/internal/cmdutil/mock.go
@@ -0,0 +1,21 @@
+package cmdutil
+
+import (
+	"crypto/sha256"
+	"fmt"
+
+	"github.com/osbuild/images/pkg/ostree"
+)
+
+func MockOSTreeResolve(commitSource ostree.SourceSpec) ostree.CommitSpec {
+	checksum := fmt.Sprintf("%x", sha256.Sum256([]byte(commitSource.URL+commitSource.Ref)))
+	spec := ostree.CommitSpec{
+		Ref:      commitSource.Ref,
+		URL:      commitSource.URL,
+		Checksum: checksum,
+	}
+	if commitSource.RHSM {
+		spec.Secrets = "org.osbuild.rhsm.consumer"
+	}
+	return spec
+}