Nothing

```
################################################################################
# Tests for utility functions
################################################################################
library("testthat")
context("Utility Functions")
test_that("xbal formula method", {
# create a quick xBalance result
df <- data.frame(Z = rep(c(1,0), 10),
X = rnorm(20))
xb <- xBalance(Z ~ X, data = df)
# we expect to have a no intercept formula
expect_equal(Z ~ X, as.formula(xb))
})
test_that("Select a subset of xbal results (for printing, etc)", {
# create a quick xBalance result
set.seed(20121129)
n <- 100
df <- data.frame(Z = rep(c(1,0), n/2),
X = rnorm(n),
Y = rnorm(n),
W = cut(rnorm(n), breaks = 3),
K = as.factor(letters[sample.int(3, n, replace = T)]),
U = rnorm(n),
S = as.factor(rep(c("A", "B"), each = n/2)))
# the data are will be grouped as (X, XY) and (all levels W by all levels
# K), Y is not in an explicit group
xb <- xBalance(Z ~ X * Y + W * K,
data = df,
strata = data.frame(none = factor("none"),
S = df$S,
U = cut(df$U, 3)),
report = 'all')
# strata based subsetion is the easiest as it common across groups and
# variables
xb.noneU <- subset(xb, strata = c("none", "U"))
expect_equivalent(dim(xb$results), c(18, 7, 3))
expect_equivalent(dim(xb.noneU$results), c(18, 7, 2))
expect_equal(attr(xb$results, "originals"),
attr(xb.noneU$results, "originals"))
# stat and test subsetion only limits the results and overall tables
# repectively
xb.zp <- subset(xb, stats = c("z", "p"))
xb.chip <- subset(xb, tests = c("chisquare", "p.value"))
expect_equivalent(xb.chip$results, xb$results)
expect_equivalent(dim(xb.zp$results), c(18, 2, 3))
expect_equivalent(dim(xb.chip$overall), c(3, 2))
expect_equal(attr(xb$results, "originals"),
attr(xb.zp$results, "originals"))
expect_equal(attr(xb$results, "originals"),
attr(xb.chip$results, "originals"))
# for vars and groups, we might want the arguments to interact more directly
# e.g. subseting vars only returns groups that include the vars
# e.g. subseting groups only returns the variables contained in those groups
# for vars, only limit the results table (for now)
# use exact variable names -- possibly use regexes later
xb.XY <- subset(xb, vars = c("X", "Y"))
expect_equivalent(dim(xb.XY$results), c(2, 7, 3))
expect_equal(length(attr(xb.XY$results, "originals")), 2)
})
```

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