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#' spec_meta_is_valid
#' @family meta specifications
#' @usage NULL
#' @format NULL
#' @keywords NULL
spec_meta_is_valid <- list(
is_valid_formals = function() {
# <establish formals of described functions>
expect_equal(names(formals(dbIsValid)), c("dbObj", "..."))
},
is_valid_connection = function(ctx) {
#' @return
#' `dbIsValid()` returns a logical scalar,
#' `TRUE` if the object specified by `dbObj` is valid,
#' `FALSE` otherwise.
con <- connect(ctx)
#' A [DBIConnection-class] object is initially valid,
expect_true(expect_visible(dbIsValid(con)))
expect_error(dbDisconnect(con), NA)
#' and becomes invalid after disconnecting with [dbDisconnect()].
expect_false(expect_visible(dbIsValid(con)))
},
#
is_valid_stale_connection = function(ctx, invalid_con) {
#' For an invalid connection object (e.g., for some drivers if the object
#' is saved to a file and then restored), the method also returns `FALSE`.
expect_false(expect_visible(dbIsValid(invalid_con)))
},
#
is_valid_result_query = function(con) {
query <- trivial_query()
res <- dbSendQuery(con, query)
on.exit(dbClearResult(res))
#' A [DBIResult-class] object is valid after a call to [dbSendQuery()],
expect_true(expect_visible(dbIsValid(res)))
expect_error(dbFetch(res), NA)
#' and stays valid even after all rows have been fetched;
expect_true(expect_visible(dbIsValid(res)))
dbClearResult(res)
on.exit(NULL)
#' only clearing it with [dbClearResult()] invalidates it.
expect_false(dbIsValid(res))
},
#
is_valid_result_statement = function(con, table_name) {
query <- paste0("CREATE TABLE ", table_name, " (a ", dbDataType(con, 1L), ")")
res <- dbSendStatement(con, query)
on.exit(dbClearResult(res))
#' A [DBIResult-class] object is also valid after a call to [dbSendStatement()],
expect_true(expect_visible(dbIsValid(res)))
#' and stays valid after querying the number of rows affected;
expect_error(dbGetRowsAffected(res), NA)
expect_true(expect_visible(dbIsValid(res)))
dbClearResult(res)
on.exit(NULL)
#' only clearing it with [dbClearResult()] invalidates it.
expect_false(dbIsValid(res))
},
#' If the connection to the database system is dropped (e.g., due to
#' connectivity problems, server failure, etc.), `dbIsValid()` should return
#' `FALSE`. This is not tested automatically.
NULL
)
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