test: do exact diff of JSON for integration

See coop-cloud/organising#627

tests/integration/server_list.bats

@@ -61,12 +61,10 @@ teardown(){
 }
 
 @test "machine readable output" {
-  run "$ABRA" server ls --machine
+  output=$("$ABRA" server ls --machine)
+
+  run diff \
+    <(jq -S "." <(echo "$output")) \
+    <(jq -S "." <(echo '[{"host":"local","name":"default"}]'))
   assert_success
-
-  expectedOutput='[{"name":"'
-  expectedOutput+="$TEST_SERVER"
-  expectedOutput+='"'
-
-  assert_output --partial "$expectedOutput"
 }