refactor(pytest): generalize option choice arg parsing

Author: scop

completions/pytest

@@ -1,5 +1,13 @@
 # bash completion for pytest(1)                            -*- shell-script -*-
 
+_pytest_option_choice_args()
+{
+    local modes=$("${2:-pytest}" $1=bash-competion-nonexistent 2>&1 |
+        command sed -e 's/[^[:space:][:alnum:]-]\{1,\}//g' \
+            -ne 's/.*choose from //p')
+    COMPREPLY+=($(compgen -W '$modes' -- "$cur"))
+}
+
 _pytest()
 {
     local cur prev words cword split
@@ -78,10 +86,7 @@ _pytest()
             return
             ;;
         --dist)
-            local modes=$("$1" --dist=nonexistent-distmode 2>&1 |
-                command sed -e 's/[^[:space:][:alnum:]-]\{1,\}//g' \
-                    -ne 's/.*choose from //p')
-            COMPREPLY=($(compgen -W '$modes' -- "$cur"))
+            _pytest_option_choice_args $prev "$1"
             return
             ;;
     esac