postfix: try to arrange a fake tty so we can tickle the usage message…

… out

completions/postfix

@@ -17,9 +17,11 @@ _postfix()
     esac
 
     if [[ $cur == -* ]]; then
-        # TODO: doesn't seem to work; the usage message doesn't get output
-        #       if we try to grep it, it's only output on the console?
-        COMPREPLY=($(compgen -W '$(_parse_usage "$1")' -- "$cur"))
+        COMPREPLY=($(
+            compgen -W \
+                '$(_bashcomp_try_faketty "$1" --help 2>&1 | _parse_usage -)' \
+                -- "$cur"
+        ))
         return
     fi
 

test/t/test_postfix.py

@@ -1,3 +1,5 @@
+import getpass
+
 import pytest
 
 
@@ -6,7 +8,15 @@ class TestPostfix:
     def test_1(self, completion):
         assert completion
 
-    @pytest.mark.xfail  # see TODO in completion
-    @pytest.mark.complete("postfix -", require_cmd=True)
-    def test_2(self, completion):
+    @pytest.mark.xfail(
+        getpass.getuser() != "root",
+        reason="Likely outputs usage only for root",
+    )
+    @pytest.mark.complete(
+        "postfix -",
+        require_cmd=True,
+        xfail="! type unbuffer &>/dev/null",
+        sleep_after_tab=2,  # postfix is slow to output usage
+    )
+    def test_options(self, completion):
         assert completion