feat: Test object returned by dbUnquoteIdentifier() is of class Id

Author: MichaelChirico

R/spec-sql-unquote-identifier.R

@@ -22,10 +22,12 @@ spec_sql_unquote_identifier <- list(
     simple_in <- dbQuoteIdentifier(con, "simple")
     simple_out <- dbUnquoteIdentifier(con, simple_in)
     expect_equal(length(simple_out), 1L)
+    expect_s4_class(simple_out[[1L]], "Id")
 
     letters_in <- dbQuoteIdentifier(con, letters)
     letters_out <- dbUnquoteIdentifier(con, letters_in)
     expect_equal(length(letters_out), length(letters_in))
+    for (obj in letters_out) expect_s4_class(obj, "Id")
 
     #' For an empty vector, this function returns a length-0 object.
     empty <- character()
@@ -44,6 +46,7 @@ spec_sql_unquote_identifier <- list(
     named_in <- dbQuoteIdentifier(con, stats::setNames(LETTERS[1:3], letters[1:3]))
     named_out <- dbUnquoteIdentifier(con, named_in)
     expect_equal(names(named_out), letters[1:3])
+    for (obj in named_out) expect_s4_class(obj, "Id")
 
     #' If `x` is a value returned by `dbUnquoteIdentifier()`,
     #' calling `dbUnquoteIdentifier(..., dbQuoteIdentifier(..., x))`