diff --git a/tests/test_rust_python_harness.py b/tests/test_rust_python_harness.py
index e01fb1dd6bb..95dfa910272 100644
--- a/tests/test_rust_python_harness.py
+++ b/tests/test_rust_python_harness.py
@@ -16,11 +16,14 @@ validate_ledger = importlib.import_module("tests.rust-python-harness.validate_le
 
 load_catalog = catalog.load_catalog
 load_ledger = ledger_module.load_ledger
+ledger_path_for = ledger_module.ledger_path_for
 REPO_ROOT = validate_ledger.REPO_ROOT
 audit_ledger = validate_ledger.audit_ledger
+build_function_report = validate_ledger.build_function_report
 _pick_values = cli._pick_values
 _coverage_pytest_args = cli._coverage_pytest_args
 _select = cli._select
+_validate_ledger = cli._validate_ledger
 CaseResult = models.CaseResult
 Coverage = models.Coverage
 HarnessCase = models.HarnessCase
@@ -242,6 +245,36 @@ def test_should_report_confidence_for_each_sdk_section() -> None:
 
 
 
+def test_should_report_no_ledger_for_a_function_without_one() -> None:
+    report = build_function_report("messages", repo_root=REPO_ROOT)
+
+    assert report.has_ledger is False
+    assert report.is_clean is True
+
+
+def test_should_report_ocr_ledger_stats_and_a_clean_audit() -> None:
+    ledger = load_ledger(ledger_path_for("ocr"))
+
+    report = build_function_report("ocr", repo_root=REPO_ROOT)
+
+    assert report.has_ledger is True
+    assert report.ledger.mapped_count == ledger.mapped_count
+    assert report.ledger.total_count == ledger.total_count
+    assert report.is_clean is True
+
+
+def test_should_scope_validate_ledger_to_the_requested_function(
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    exit_code = _validate_ledger({"messages"})
+
+    captured = capsys.readouterr()
+    assert exit_code == 0
+    assert "messages" in captured.out
+    assert "no ledger yet" in captured.out
+    assert "ocr" not in captured.out
+
+
 def test_should_have_every_python_and_rust_ocr_test_accounted_for_in_the_ledger() -> None:
     ledger = load_ledger()