R Under development (unstable) (2024-06-25 r86831 ucrt) -- "Unsuffered Consequences"
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> ## regression test for PR#15346
> 
> library(foreign)
> 
> ## The testEmpty.xpt dataset was created using the following code:
> ## library(SASxport)
> ## data(iris)
> ## write.xport(Iris1=iris[1:2,],    # two row dataset
> ##             empty=data.frame(),  # empty dataset
> ##             Iris2=iris[3:4,],    # two row dataset
> ##             file="testEmpty.xpt",
> ##             autogen.formats=FALSE # prevent autocreation of FORMATS dataset
> ##             )
> 
> ## Test that lookup.xport retrieves all three datsets
> empty.f <- lookup.xport(file="testEmpty.xpt")
> empty.f
$IRIS1
$IRIS1$headpad
[1] 1200

$IRIS1$type
[1] "numeric"   "numeric"   "numeric"   "numeric"   "character"

$IRIS1$width
[1] 8 8 8 8 8

$IRIS1$index
[1] 1 2 3 4 5

$IRIS1$position
[1]  0  8 16 24 32

$IRIS1$name
[1] "SEPAL_LE" "SEPAL_WI" "PETAL_LE" "PETAL_WI" "SPECIES" 

$IRIS1$label
[1] "" "" "" "" ""

$IRIS1$format
[1] "" "" "" "" ""

$IRIS1$sexptype
[1] 14 14 14 14 16

$IRIS1$tailpad
[1] 0

$IRIS1$length
[1] 2


$EMPTY
$EMPTY$headpad
[1] 480

$EMPTY$type
character(0)

$EMPTY$width
integer(0)

$EMPTY$index
integer(0)

$EMPTY$position
integer(0)

$EMPTY$name
character(0)

$EMPTY$label
character(0)

$EMPTY$format
character(0)

$EMPTY$sexptype
integer(0)

$EMPTY$tailpad
[1] 0

$EMPTY$length
[1] 0


$IRIS2
$IRIS2$headpad
[1] 1200

$IRIS2$type
[1] "numeric"   "numeric"   "numeric"   "numeric"   "character"

$IRIS2$width
[1] 8 8 8 8 8

$IRIS2$index
[1] 1 2 3 4 5

$IRIS2$position
[1]  0  8 16 24 32

$IRIS2$name
[1] "SEPAL_LE" "SEPAL_WI" "PETAL_LE" "PETAL_WI" "SPECIES" 

$IRIS2$label
[1] "" "" "" "" ""

$IRIS2$format
[1] "" "" "" "" ""

$IRIS2$sexptype
[1] 14 14 14 14 16

$IRIS2$tailpad
[1] 0

$IRIS2$length
[1] 2


> stopifnot(length(empty.f) == 3L)
> 
> 
> dat.f <- read.xport(file="testEmpty.xpt")
> dat.f
$IRIS1
  SEPAL_LE SEPAL_WI PETAL_LE PETAL_WI SPECIES
1      5.1      3.5      1.4      0.2  setosa
2      4.9      3.0      1.4      0.2  setosa

$EMPTY
data frame with 0 columns and 0 rows

$IRIS2
  SEPAL_LE SEPAL_WI PETAL_LE PETAL_WI SPECIES
1      4.7      3.2      1.3      0.2  setosa
2      4.6      3.1      1.5      0.2  setosa

> stopifnot(length(dat.f)==3)
> 
> 
> proc.time()
   user  system elapsed 
   0.21    0.04    0.25