{
  "valid": [
    "assignee is empty",
    "assignee is not empty",
    "assignee is EmPtY",
    "assignee is not EmPtY",
    "assignee is null",
    "assignee is not null",
    "assignee Is empty",
    "assignee iS empty",
    "assignee Is nOt empty",
    "assignee is    not empty",
    "assignee is\nnot empty"
  ],
  "invalid": [
    "assignee is",
    "assignee is not",
    "assignee is b",
    "assignee is not b",
    "assignee is 0",
    "assignee is not 0",
    "assignee is -5",
    "assignee is not -5",
    "assignee is currentUser()",
    "assignee is not currentUser()",
    "assignee is (a, b)",
    "assignee is not (a, b)",
    "assignee is empty after -1w",
    "assignee is not empty after -1w",
    "assignee is empty before -1w",
    "assignee is not empty before -1w",
    "assignee is empty on -1w",
    "assignee is not empty on -1w",
    "assignee is empty during (-1w, now())",
    "assignee is not empty during (-1w, now())",
    "assignee is empty by b",
    "assignee is not empty by b",
    "assignee is empty from b",
    "assignee is not empty from b",
    "assignee is empty to b",
    "assignee is not empty to b"
  ]
}