update unit test

Author: HajkD

tests/testthat/test-file_contains.R

@@ -6,7 +6,7 @@ test_that("file_contains_aa() works properly with input aa fasta file ...", {
 })
 
 test_that("file_contains_aa() throws error when input file contains dna rather than aa ...", {
-  expect_error(file_contains_aa(system.file('seqs/qry_nn.fa', package = 'metablastr'), "query"))
+  expect_warning(file_contains_aa(system.file('seqs/qry_nn.fa', package = 'metablastr'), "query"))
 
 })
 
@@ -16,7 +16,7 @@ test_that("file_contains_dna() works properly with input dna fasta file ...", {
 })
 
 test_that("file_contains_dna() throws error when input file contains aa rather than dna ...", {
-  expect_error(file_contains_dna(system.file('seqs/qry_aa.fa', package = 'metablastr'), "query")
+  expect_warning(file_contains_dna(system.file('seqs/qry_aa.fa', package = 'metablastr'), "query")
 )
 
 })