Does code return an object inheriting from the expected base type, S3 class, or S4 class?
See https://adv-r.hadley.nz/oo.html for an overview of R's OO systems, and the vocabulary used here.
expect_type(x, type) checks that typeof(x) is type.
expect_s3_class(x, class) checks that x is an S3 object that
inherits() from class
expect_s3_class(x, NA) checks that x isn't an S3 object.
expect_s4_class(x, class) checks that x is an S4 object that
is() class.
expect_s4_class(x, NA) checks that x isn't an S4 object.
See expect_vector() for testing properties of objects created by vctrs.
expect_type(object, type) expect_s3_class(object, class, exact = FALSE) expect_s4_class(object, class)
object |
Object to test. Supports limited unquoting to make it easier to generate readable failures within a function or for loop. See quasi_label for more details. |
type |
String giving base type (as returned by |
class |
Either a character vector of class names, or
for |
exact |
If |
Other expectations:
comparison-expectations,
equality-expectations,
expect_error(),
expect_length(),
expect_match(),
expect_named(),
expect_null(),
expect_output(),
expect_reference(),
expect_silent(),
logical-expectations
x <- data.frame(x = 1:10, y = "x", stringsAsFactors = TRUE) # A data frame is an S3 object with class data.frame expect_s3_class(x, "data.frame") show_failure(expect_s4_class(x, "data.frame")) # A data frame is built from a list: expect_type(x, "list") # An integer vector is an atomic vector of type "integer" expect_type(x$x, "integer") # It is not an S3 object show_failure(expect_s3_class(x$x, "integer")) # Above, we requested data.frame() converts strings to factors: show_failure(expect_type(x$y, "character")) expect_s3_class(x$y, "factor") expect_type(x$y, "integer")
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