```
# create test data frame
df <- data.frame(
week_payment1 = c(1, 2, 3),
week_payment2 = c(4, 5, 6),
week_payment3 = c(7, 8, 9),
other_column = c(10, 11, 12)
)
# test for df is not a data frame
test_that("calculate_standard_deviation() errors when df is not a data frame", {
df <- 1
expect_error(calculate_standard_deviation(df, "week_payment"))
})
# test for pattern is not a character
test_that("calculate_standard_deviation() errors when pattern is not a character", {
expect_error(calculate_standard_deviation(df, 1))
})
# test for pattern is not found
test_that("calculate_standard_deviation() errors when pattern not found", {
expect_error(calculate_standard_deviation(df, "no_matching_pattern"))
})
# test for return type
test_that("calculate_standard_deviation() returns a numeric vector", {
result <- calculate_standard_deviation(df, "week_payment")
expect_type(result, "double")
})
# test for data frame with only 1 column
test_that("calculate_standard_deviation() returns correct value", {
df <- data.frame(
week_payment1 = c(1, 2, 3)
)
result <- calculate_standard_deviation(df, "week_payment")
expect_equal(result, c(0, 0, 0))
})
# test for data frame with only 1 row
test_that("calculate_standard_deviation() returns correct value", {
df <- data.frame(
week_payment1 = c(1)
)
result <- calculate_standard_deviation(df, "week_payment")
expect_equal(result, c(0))
})
# test for return correct value
test_that("calculate_standard_deviation() returns correct average", {
result <- calculate_standard_deviation(df, "week_payment")
expect_equal(result, c(6**0.5, 6**0.5, 6**0.5))
})
```

Embedding an R snippet on your website

Add the following code to your website.

For more information on customizing the embed code, read Embedding Snippets.