Clarify types in class expectations

Fixes #1989

Author: hadley

R/expect-inheritance.R

@@ -21,13 +21,13 @@
 #'
 #' @param type String giving base type (as returned by [typeof()]).
 #' @param class
-#'  * `expect_type()`: a single string giving an R base type.
+#'  * `expect_type()`: a string.
 #'  * `expect_s3_class()`: a character vector of class names or `NA` to assert
 #'    that `object` isn't an S3 object. If you provide multiple class names,
 #'    the test will pass if `object` inherits from any of them, unless
 #'    `exact = TRUE`.
-#'  * `expect_s4_class()`: a character vector of class names or `NA` to assert
-#'    that `object` isn't an S4 object.
+#'  * `expect_s4_class()`: a string or `NA` to assert that `object` isn't an
+#'    S4 object.
 #'  * `expect_r6_class()`: a string.
 #'  * `expect_s7_class()`: an [S7::S7_class()] object.
 #' @inheritParams expect_that