refactor: remove ps command

`ps` should be replaced by `enter` with a specified container id.

tests/unit/10_ps-dockerfile.bats

@@ -12,17 +12,6 @@ teardown() {
   global_teardown
 }
 
-# @test "(ps) dockerfile base" {
-#   # CI support: 'Ah. I just spoke with our Docker expert --
-#   # looks like docker exec is built to work with docker-under-libcontainer,
-#   # but we're using docker-under-lxc. I don't have an estimated time for the fix, sorry
-#   skip "circleci does not support docker exec at the moment."
-#   run /bin/bash -c "dokku ps $TEST_APP | grep -q \"node web.js\""
-#   echo "output: $output"
-#   echo "status: $status"
-#   assert_success
-# }
-
 @test "(ps) dockerfile" {
   deploy_app dockerfile
   run /bin/bash -c "dokku ps:stop $TEST_APP"

tests/unit/10_ps-general.bats

@@ -13,10 +13,17 @@ teardown() {
 }
 
 @test "(ps) ps:help" {
+  run /bin/bash -c "dokku ps"
+  echo "output: $output"
+  echo "status: $status"
+  assert_output_contains "Manage container processes"
+  help_output="$output"
+
   run /bin/bash -c "dokku ps:help"
   echo "output: $output"
   echo "status: $status"
   assert_output_contains "Manage container processes"
+  assert_output "$help_output"
 }
 
 @test "(ps) ps:inspect" {

tests/unit/10_ps-herokuish.bats

@@ -13,18 +13,6 @@ teardown() {
   global_teardown
 }
 
-# @test "(ps) herokuish base" {
-#   # CI support: 'Ah. I just spoke with our Docker expert --
-#   # looks like docker exec is built to work with docker-under-libcontainer,
-#   # but we're using docker-under-lxc. I don't have an estimated time for the fix, sorry
-#   skip "circleci does not support docker exec at the moment."
-#   deploy_app
-#   run /bin/bash -c "dokku ps $TEST_APP | grep -q \"node web.js\""
-#   echo "output: $output"
-#   echo "status: $status"
-#   assert_success
-# }
-
 @test "(ps) herokuish" {
   deploy_app
   run /bin/bash -c "dokku ps:stop $TEST_APP"