1 files changed, 92 insertions, 0 deletions
diff --git a/scripts/test_nix_cargo_hash.py b/scripts/test_nix_cargo_hash.py
new file mode 100644
index 00000000..c00b1a6c
--- /dev/null
+++ b/scripts/test_nix_cargo_hash.py
@@ -0,0 +1,92 @@
+from __future__ import annotations
+
+import unittest
+
+from scripts.nix_cargo_hash import (
+    NixCargoHashError,
+    check_cargo_hash,
+    find_cargo_hash_assignment,
+    parse_got_hash,
+    replace_cargo_hash_assignment,
+)
+
+
+PACKAGE_TEXT = """
+rustPlatform.buildRustPackage {
+  pname = "herdr";
+  cargoHash = "sha256-oldHash=";
+}
+"""
+
+
+class NixCargoHashTests(unittest.TestCase):
+    def test_find_cargo_hash_assignment_reads_single_hash(self) -> None:
+        self.assertEqual(find_cargo_hash_assignment(PACKAGE_TEXT), '"sha256-oldHash="')
+
+    def test_replace_cargo_hash_assignment_updates_single_hash(self) -> None:
+        updated = replace_cargo_hash_assignment(PACKAGE_TEXT, '"sha256-newHash="')
+
+        self.assertIn('cargoHash = "sha256-newHash=";', updated)
+        self.assertNotIn("sha256-oldHash", updated)
+
+    def test_replace_cargo_hash_assignment_accepts_fake_hash(self) -> None:
+        updated = replace_cargo_hash_assignment(PACKAGE_TEXT, "lib.fakeHash")
+
+        self.assertIn("cargoHash = lib.fakeHash;", updated)
+
+    def test_replace_cargo_hash_assignment_rejects_missing_hash(self) -> None:
+        with self.assertRaisesRegex(NixCargoHashError, "found 0"):
+            replace_cargo_hash_assignment('pname = "herdr";\n', "lib.fakeHash")
+
+    def test_replace_cargo_hash_assignment_rejects_multiple_hashes(self) -> None:
+        text = PACKAGE_TEXT + PACKAGE_TEXT
+
+        with self.assertRaisesRegex(NixCargoHashError, "found 2"):
+            replace_cargo_hash_assignment(text, "lib.fakeHash")
+
+    def test_parse_got_hash_reads_nix_hash_mismatch(self) -> None:
+        output = """
+        specified: sha256-oldHash=
+             got: sha256-newHash123+/=
+        """
+
+        self.assertEqual(parse_got_hash(output), "sha256-newHash123+/=")
+
+    def test_parse_got_hash_rejects_missing_hash(self) -> None:
+        with self.assertRaisesRegex(NixCargoHashError, "found 0"):
+            parse_got_hash("error: no hash here")
+
+    def test_parse_got_hash_rejects_multiple_hashes(self) -> None:
+        output = "got: sha256-one=\ngot: sha256-two=\n"
+
+        with self.assertRaisesRegex(NixCargoHashError, "found 2"):
+            parse_got_hash(output)
+
+    def test_check_cargo_hash_restores_file_on_failure(self) -> None:
+        import contextlib
+        import io
+        import tempfile
+        from pathlib import Path
+        from unittest import mock
+
+        with tempfile.TemporaryDirectory() as temp_dir:
+            package = Path(temp_dir) / "package.nix"
+            package.write_text(PACKAGE_TEXT, encoding="utf-8")
+
+            with mock.patch("scripts.nix_cargo_hash.shutil.which", return_value="/nix/bin/nix"):
+                with mock.patch("scripts.nix_cargo_hash.run_capture") as run_capture:
+                    run_capture.side_effect = [
+                        mock.Mock(returncode=0, stdout="x86_64-linux"),
+                        mock.Mock(returncode=1, stdout="error without got hash"),
+                    ]
+
+                    with contextlib.redirect_stdout(io.StringIO()):
+                        with self.assertRaisesRegex(NixCargoHashError, "found 0"):
+                            check_cargo_hash(package)
+
+            self.assertIn("--no-link", run_capture.call_args_list[1].args[0])
+            self.assertEqual(package.read_text(encoding="utf-8"), PACKAGE_TEXT)
+
+
+if __name__ == "__main__":
+    unittest.main()