make output file argument required

src/gffread/config.vsh.yaml

@@ -51,9 +51,10 @@ argument_groups:
         type: file
         direction: output
         must_exist: false
+        required: true
         description: |
           Write the output records into <outfile>.
-        default: output.gff
+        example: output.gff
       - name: --force_exons
         type: boolean_true
         description: |

src/gffread/script.sh

@@ -55,7 +55,7 @@ gffread \
     "$par_input" \
     ${par_chr_mapping:+-m "$par_chr_mapping"} \
     ${par_seq_info:+-s "$par_seq_info"} \
-    ${par_outfile:+-o "$par_outfile"} \
+    -o "$par_outfile" \
     ${par_force_exons:+--force-exons} \
     ${par_gene2exon:+--gene2exon} \
     ${par_t_adopt:+--t-adopt} \

src/gffread/test.sh

@@ -62,10 +62,10 @@ diff "$expected_output_dir/annotation.gtf" "$test_output_dir/annotation.gtf" ||
 
 echo "> Test 3 - Generate fasta file from annotation file"
 
-
 "$meta_executable" \
   --genome "$test_dir/sequence.fasta" \
   --spliced_exons "$test_output_dir/transcripts.fa" \
+  --outfile "$test_output_dir/output.gff" \
   --input "$test_dir/sequence.gff3"
 
 echo ">> Check if output exists"