Add an extra test for sanity (#411)

Author: MichaelChirico

R/spec-sql-write-table.R

@@ -88,6 +88,7 @@ spec_sql_write_table <- list(
     expect_error(dbWriteTable(con, table_name, test_in, field.types = c("INTEGER")))
 
     #' incompatible columns)
+    expect_false(dbExistsTable(con, table_name))
     dbWriteTable(con, table_name, test_in)
     expect_error(dbWriteTable(con, table_name, data.frame(b = 2L, c = 3L), append = TRUE))