diff --git a/tests/lib/rewatch.lock b/tests/lib/rewatch.lock
new file mode 100644
index 0000000..da27e6c
--- /dev/null
+++ b/tests/lib/rewatch.lock
@@ -0,0 +1 @@
+57150
\ No newline at end of file
diff --git a/tests/suffix.sh b/tests/suffix.sh
new file mode 100755
index 0000000..a7fe978
--- /dev/null
+++ b/tests/suffix.sh
@@ -0,0 +1,56 @@
+source "./utils.sh"
+cd ../testrepo
+
+bold "Test: It should support custom suffixes"
+
+# Clean Repo
+sleep 1
+if rewatch clean &> /dev/null;
+then
+  success "Repo Cleaned"
+else 
+  error "Error Cleaning Repo"
+  exit 1
+fi
+
+# Replace suffix
+replace "s/.mjs/.res.js/g" bsconfig.json
+
+if rewatch build &> /dev/null;
+then
+  success "Repo Built"
+else 
+  error "Error building repo"
+  exit 1
+fi
+
+# Count files with new extension
+file_count=$(find . -name *.res.js | wc -l)
+
+if [ "$file_count" -eq 9 ];
+then
+  success "Found files with correct suffix"
+else 
+  error "Suffix not correctly used"
+  exit 1
+fi
+
+if rewatch clean &> /dev/null;
+then
+  success "Repo Cleaned"
+else 
+  error "Error Cleaning Repo"
+  exit 1
+fi
+
+# Restore Suffix
+replace "s/.res.js/.mjs/g" bsconfig.json
+
+# Restore original build
+if rewatch build &> /dev/null;
+then
+  success "Repo Built"
+else 
+  error "Error building repo"
+  exit 1
+fi
diff --git a/tests/suite-ci.sh b/tests/suite-ci.sh
index d0f883f..bcec567 100755
--- a/tests/suite-ci.sh
+++ b/tests/suite-ci.sh
@@ -22,4 +22,4 @@ else
   exit 1
 fi
 
-./compile.sh && ./watch.sh && ./lock.sh
+./compile.sh && ./watch.sh && ./lock.sh && ./suffix.sh