1 files changed, 26 insertions, 0 deletions
diff --git a/internal/testgit/revparse.go b/internal/testgit/revparse.go
new file mode 100644
index 00000000..ffa5b702
--- /dev/null
+++ b/internal/testgit/revparse.go
@@ -0,0 +1,26 @@
+package testgit
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"lindenii.org/go/furgit/object/id"
+)
+
+// RevParse resolves one revision spec to an object ID.
+func (repo *Repo) RevParse(tb testing.TB, spec string) (id.ObjectID, error) {
+	tb.Helper()
+
+	stdout, err := repo.run(tb, nil, "git", "rev-parse", "--verify", "--end-of-options", spec)
+	if err != nil {
+		return id.ObjectID{}, fmt.Errorf("rev-parse %q: %w", spec, err)
+	}
+
+	objectID, err := repo.objectFormat.FromString(strings.TrimSuffix(string(stdout), "\n"))
+	if err != nil {
+		return id.ObjectID{}, fmt.Errorf("parse git rev-parse output %q: %w", string(stdout), err)
+	}
+
+	return objectID, nil
+}