From 58b0185d3458d0b495d5e2917de78bf94ead9304 Mon Sep 17 00:00:00 2001
From: Wonchan Lee <wonchanl@nvidia.com>
Date: Tue, 23 Feb 2021 13:55:56 -0800
Subject: [PATCH] Add a failing test case that passes a leading null to scan
 with skipna=False

---
 cpp/tests/reductions/scan_tests.cpp | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/cpp/tests/reductions/scan_tests.cpp b/cpp/tests/reductions/scan_tests.cpp
index 2b7faa32316..5abcb5a6402 100644
--- a/cpp/tests/reductions/scan_tests.cpp
+++ b/cpp/tests/reductions/scan_tests.cpp
@@ -470,6 +470,32 @@ TYPED_TEST(ScanTest, EmptyColumnskip_nulls)
   CUDF_TEST_EXPECT_COLUMNS_EQUAL(expected_col_out2, col_out->view());
 }
 
+TYPED_TEST(ScanTest, LeadingNulls)
+{
+  bool do_print = true;
+  auto const v  = cudf::test::make_type_param_vector<TypeParam>({100, 200, 300});
+  auto const b  = std::vector<bool>{0, 1, 1};
+  cudf::test::fixed_width_column_wrapper<TypeParam> const col_in(v.begin(), v.end(), b.begin());
+  std::unique_ptr<cudf::column> col_out;
+
+  // expected outputs
+  std::vector<TypeParam> out_v(v.size());
+  std::vector<bool> out_b(v.size(), 0);
+
+  // skipna=false
+  CUDF_EXPECT_NO_THROW(
+    col_out =
+      cudf::scan(col_in, cudf::make_sum_aggregation(), scan_type::INCLUSIVE, null_policy::INCLUDE));
+  cudf::test::fixed_width_column_wrapper<TypeParam> expected_col_out(
+    out_v.begin(), out_v.end(), out_b.begin());
+  if (do_print) {
+    print_view(expected_col_out, "expect = ");
+    print_view(col_out->view(), "result = ");
+  }
+  CUDF_TEST_EXPECT_COLUMN_PROPERTIES_EQUAL(expected_col_out, col_out->view());
+  CUDF_TEST_EXPECT_COLUMNS_EQUAL(expected_col_out, col_out->view());
+}
+
 template <typename T>
 struct FixedPointTestBothReps : public cudf::test::BaseFixture {
 };