document it, add error, remove test

bin/ch-convert

@@ -865,6 +865,9 @@ done
 if [ "$#" -ne 2 ]; then
     usage
 fi
+if [ $verbose -gt 0 ] && [ $quiet -gt 0 ]; then
+    FATAL "incompatible options: --quiet, --verbose"
+fi
 if [ -n "$no_xattrs" ]; then
     tar_xattr_args=
     squash_xattr_arg=

doc/ch-convert.rst

@@ -56,7 +56,8 @@ producing the final format actually needed.
     Output image format is :code:`FMT`; inferred if omitted.
 
   :code:`-q`, :code:`--quiet`
-    Suppress program output. Note that this does not suppress errors.
+    Be quieter; can be repeated. Incompatible with :code:`-v`. See the :ref:`FAQ
+    entry on verbosity <faq_verbosity>` for details.
 
   :code:`-s`, :code:`--storage DIR`
     Set the storage directory. Equivalent to the same option for :code:`ch-image(1)`

test/run/ch-convert.bats

@@ -564,24 +564,6 @@ EOF
     [[ $output = *"user:$USER:r--"* ]]
 }
 
-
-@test 'ch-convert: --quiet' {
-    printf 'FROM alpine:3.17\n' | ch-image build -t tmpimg -f - "$BATS_TMPDIR"
-
-    # successful convert
-    run ch-convert -q -i ch-image -o dir tmpimg "${BATS_TMPDIR}/tmpimg"
-    echo "$output"
-    [[ $status -eq 0 ]]
-    [[ -z "$output" ]]
-
-    # failed convert
-    run ch-convert -q -i dir -o dir "${BATS_TMPDIR}/tmpimg" "${BATS_TMPDIR}/tmpimg2"
-    echo "$output"
-    [[ $status -eq 1 ]]
-    [[ "$output" = *'error: input and output formats must be different'* ]]
-}
-
-
 @test 'ch-convert: dir -> ch-image -> X' {
     test_from ch-image
 }