diff --git a/modules/cat/cat/main.nf b/modules/cat/cat/main.nf
index 09a41561..40e53f3e 100644
--- a/modules/cat/cat/main.nf
+++ b/modules/cat/cat/main.nf
@@ -49,6 +49,8 @@ process CAT_CAT {
     """
 
     stub:
+    def file_list = files_in.collect { it.toString() }
+    prefix   = task.ext.prefix ?: "${meta.id}${file_list[0].substring(file_list[0].lastIndexOf('.'))}"
     """
     touch $prefix
 
diff --git a/tests/modules/cat/cat/test.yml b/tests/modules/cat/cat/test.yml
index d6e6595e..9710b665 100644
--- a/tests/modules/cat/cat/test.yml
+++ b/tests/modules/cat/cat/test.yml
@@ -7,6 +7,14 @@
     - path: output/cat/test.fasta
       md5sum: f44b33a0e441ad58b2d3700270e2dbe2
 
+- name: cat unzipped unzipped stub
+  command: nextflow run ./tests/modules/cat/cat -entry test_cat_unzipped_unzipped -c ./tests/config/nextflow.config -c ./tests/modules/cat/cat/nextflow.config -stub-run
+  tags:
+    - cat
+    - cat/cat
+  files:
+    - path: output/cat/test.fasta
+
 - name: cat zipped zipped
   command: nextflow run ./tests/modules/cat/cat -entry test_cat_zipped_zipped -c ./tests/config/nextflow.config -c ./tests/modules/cat/cat/nextflow.config
   tags:
@@ -15,6 +23,14 @@
   files:
     - path: output/cat/test.gz
 
+- name: cat zipped zipped stub
+  command: nextflow run ./tests/modules/cat/cat -entry test_cat_zipped_zipped -c ./tests/config/nextflow.config -c ./tests/modules/cat/cat/nextflow.config -stub-run
+  tags:
+    - cat
+    - cat/cat
+  files:
+    - path: output/cat/test.gz
+
 - name: cat zipped unzipped
   command: nextflow run ./tests/modules/cat/cat -entry test_cat_zipped_unzipped -c ./tests/config/nextflow.config -c ./tests/modules/cat/cat/nextflow.config
   tags:
@@ -24,6 +40,14 @@
     - path: output/cat/cat.txt
       md5sum: c439d3b60e7bc03e8802a451a0d9a5d9
 
+- name: cat zipped unzipped stub
+  command: nextflow run ./tests/modules/cat/cat -entry test_cat_zipped_unzipped -c ./tests/config/nextflow.config -c ./tests/modules/cat/cat/nextflow.config -stub-run
+  tags:
+    - cat
+    - cat/cat
+  files:
+    - path: output/cat/cat.txt
+
 - name: cat unzipped zipped
   command: nextflow run ./tests/modules/cat/cat -entry test_cat_unzipped_zipped -c ./tests/config/nextflow.config -c ./tests/modules/cat/cat/nextflow.config
   tags:
@@ -32,6 +56,14 @@
   files:
     - path: output/cat/cat.txt.gz
 
+- name: cat unzipped zipped stub
+  command: nextflow run ./tests/modules/cat/cat -entry test_cat_unzipped_zipped -c ./tests/config/nextflow.config -c ./tests/modules/cat/cat/nextflow.config -stub-run
+  tags:
+    - cat
+    - cat/cat
+  files:
+    - path: output/cat/cat.txt.gz
+
 - name: cat one file unzipped zipped
   command: nextflow run ./tests/modules/cat/cat -entry test_cat_one_file_unzipped_zipped -c ./tests/config/nextflow.config -c ./tests/modules/cat/cat/nextflow.config
   tags:
@@ -39,3 +71,11 @@
     - cat/cat
   files:
     - path: output/cat/cat.txt.gz
+
+- name: cat one file unzipped zipped stub
+  command: nextflow run ./tests/modules/cat/cat -entry test_cat_one_file_unzipped_zipped -c ./tests/config/nextflow.config -c ./tests/modules/cat/cat/nextflow.config -stub-run
+  tags:
+    - cat
+    - cat/cat
+  files:
+    - path: output/cat/cat.txt.gz