1 files changed, 112 insertions, 0 deletions
diff --git a/src/arrow/r/tests/testthat/test-scalar.R b/src/arrow/r/tests/testthat/test-scalar.R
new file mode 100644
index 000000000..3afccf743
--- /dev/null
+++ b/src/arrow/r/tests/testthat/test-scalar.R
@@ -0,0 +1,112 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+
+expect_scalar_roundtrip <- function(x, type) {
+  s <- Scalar$create(x)
+  expect_r6_class(s, "Scalar")
+  expect_equal(s$type, type)
+  expect_identical(length(s), 1L)
+  if (inherits(type, "NestedType")) {
+    # Should this be? Missing if all elements are missing?
+    # expect_identical(is.na(s), all(is.na(x))) # nolint
+  } else {
+    expect_identical(as.vector(is.na(s)), is.na(x))
+    # MakeArrayFromScalar not implemented for list types
+    expect_as_vector(s, x)
+  }
+}
+
+test_that("Scalar object roundtrip", {
+  expect_scalar_roundtrip(2, float64())
+  expect_scalar_roundtrip(2L, int32())
+  expect_scalar_roundtrip(c(2, 4), list_of(float64()))
+  expect_scalar_roundtrip(c(NA, NA), list_of(bool()))
+  expect_scalar_roundtrip(data.frame(a = 2, b = 4L), struct(a = double(), b = int32()))
+})
+
+test_that("Scalar print", {
+  expect_output(print(Scalar$create(4)), "Scalar\n4")
+})
+
+test_that("Creating Scalars of a different type and casting them", {
+  expect_equal(Scalar$create(4L, int8())$type, int8())
+  expect_equal(Scalar$create(4L)$cast(float32())$type, float32())
+})
+
+test_that("Scalar to Array", {
+  a <- Scalar$create(42)
+  expect_equal(a$as_array(), Array$create(42))
+  expect_equal(Array$create(a), Array$create(42))
+})
+
+test_that("Scalar$Equals", {
+  a <- Scalar$create(42)
+  aa <- Array$create(42)
+  b <- Scalar$create(42)
+  d <- Scalar$create(43)
+  expect_equal(a, b)
+  expect_true(a$Equals(b))
+  expect_false(a$Equals(d))
+  expect_false(a$Equals(aa))
+})
+
+test_that("Scalar$ApproxEquals", {
+  a <- Scalar$create(1.0000000000001)
+  aa <- Array$create(1.0000000000001)
+  b <- Scalar$create(1.0)
+  d <- 2.400000000000001
+  expect_false(a$Equals(b))
+  expect_true(a$ApproxEquals(b))
+  expect_false(a$ApproxEquals(d))
+  expect_false(a$ApproxEquals(aa))
+})
+
+test_that("Handling string data with embedded nuls", {
+  raws <- as.raw(c(0x6d, 0x61, 0x00, 0x6e))
+  expect_error(
+    rawToChar(raws),
+    "embedded nul in string: 'ma\\0n'", # See?
+    fixed = TRUE
+  )
+  scalar_with_nul <- Scalar$create(raws, binary())$cast(utf8())
+
+  # The behavior of the warnings/errors is slightly different with and without
+  # altrep. Without it (i.e. 3.5.0 and below, the error would trigger immediately
+  # on `as.vector()` where as with it, the error only happens on materialization)
+  skip_if_r_version("3.5.0")
+  v <- expect_error(as.vector(scalar_with_nul), NA)
+  expect_error(
+    v[1],
+    paste0(
+      "embedded nul in string: 'ma\\0n'; to strip nuls when converting from Arrow to R, ",
+      "set options(arrow.skip_nul = TRUE)"
+    ),
+    fixed = TRUE
+  )
+
+  withr::with_options(list(arrow.skip_nul = TRUE), {
+    expect_warning(
+      expect_identical(
+        as.vector(scalar_with_nul)[],
+        "man"
+      ),
+      "Stripping '\\0' (nul) from character vector",
+      fixed = TRUE
+    )
+  })
+})