diff --git a/update_legend-testdata.jl b/update_legend-testdata.jl
new file mode 100644
index 0000000..ef697a8
--- /dev/null
+++ b/update_legend-testdata.jl
@@ -0,0 +1,56 @@
+import Pkg, Artifacts
+Pkg.activate(temp = true)
+Pkg.add(["ArtifactUtils", "HTTP", "JSON"])
+using ArtifactUtils, Artifacts
+import HTTP, JSON
+
+pkg_dir = joinpath(dirname(@__DIR__), "LegendTestData")
+cd(pkg_dir)
+Pkg.activate(pkg_dir)
+
+project_path = Pkg.project().path
+project = Pkg.Types.read_project(project_path)
+package_name = "LegendTestData"
+@assert project.name == package_name
+
+testdata_commit_info_url = "https://api.github.com/repos/legend-exp/legend-testdata/commits/main"
+testdata_commit_id = JSON.parse(String(HTTP.get(testdata_commit_info_url).body))["sha"]
+testdata_commit_id_short = testdata_commit_id[begin:begin+6]
+
+artifact_id = add_artifact!(
+    "Artifacts.toml",
+    "legend_testdata",
+    "https://api.github.com/repos/legend-exp/legend-testdata/tarball/" * testdata_commit_id,
+    force = true
+)
+Pkg.ensure_artifact_installed("legend_testdata", "Artifacts.toml")
+@info "Updated legend-testdata artifact"
+
+main_src_file = joinpath("src", "LegendTestData.jl")
+
+write(
+    main_src_file,
+    replace(
+        read(main_src_file, String),
+        r"const _legend_testdata_commit=\".*\"" => "const _legend_testdata_commit=\"$testdata_commit_id_short\""
+    )
+)
+@info "Updated $main_src_file."
+
+package_version = project.version
+vmajor, vminor, vpatch = package_version.major, package_version.minor, package_version.patch
+new_package_version = VersionNumber(vmajor, vminor, vpatch + 1)
+project.version = new_package_version
+Pkg.Types.write_project(project, project_path)
+@assert Pkg.project().version == new_package_version
+@info "Increased version of $package_name from $package_version to $new_package_version."
+
+rm("Manifest.toml", force = true)
+Pkg.test("LegendTestData")
+rm("Manifest.toml", force = true)
+
+git_branch = git_branch = strip(read(`git rev-parse --abbrev-ref HEAD`, String))
+run(`git add "Project.toml" "Artifacts.toml" $main_src_file`)
+run(`git commit -m "Update legend-testdata to $testdata_commit_id_short, increase package version to $new_package_version"`)
+@info "Commited changes to package $package_name to branch $git_branch."
+println("Run `git push origin $git_branch` to push the changes.")