自定义 Template Test

  {% if 7 is prime %}7 是质数{% endif %}                        → 7 是质数
  {% if 8 is prime %}8 是质数{% else %}8 不是质数{% endif %}        → 8 不是质数
  {{ 11 is prime }}|{{ 12 is not prime }}                    → True|True
  {{ "hello" is longer_than(3) }}|{{ "hi" is longer_than 3 }} → True|False
  {{ user is adult }}                                        → True
  {{ d is weekend }}                                         → True
  {{ "a@b.co" is email }}|{{ "nope" is email }}              → True|False
  {{ doc is mine }}|{{ other is mine }}                      → True|False

   [2, 3, 5, 7] | [1, 4, 6, 8, 9, 10] | ['b']
  select("longer_than", 2): ['abc', 'abcd']

  0 is defined           → True
  缺失 is defined          → False
  x is none(None)        → True
  x is none(0)           → False
  if x(0)                → 假
  x is true(1)           → False
  x is true(True)        → True
  "" is string           → True
  x is number(True)      → True
  4 is divisibleby 2     → True
  3 is odd               → True
  x is mapping           → True
  x is iterable(str)     → True
  x is callable          → True
  1 is eq 1              → True
  3 is ge 2              → True
  "a" is in ["a","b"]    → True
  x is sameas none       → True

  不存在的测试 → TemplateAssertionError: No test named 'nope'.
  缺少必需参数 → TypeError: longer_than() missing 1 required positional argument: 'n'
  给了多余的参数 → TypeError: is_prime() takes 1 positional argument but 2 were given
  对非整数用 prime(自己的函数返回 False 而不抛)→ False | 测试里没处理 None 时的报错(这里的 adult 收到 None): AttributeError: 'NoneType' object has no attribute 'get'

  共 45 个: != < <= == > >= adult boolean callable defined divisibleby email eq equalto escaped even false filter float ge greaterthan gt in integer iterable le lessthan longer_than lower lt mapping mine ne none number odd prime sameas sequence string test true undefined upper weekend

  n is prime(测试)           5.10 µs/次
  n|prime_f(过滤器)           5.11 µs/次
  prime_g(n)(全局函数)         6.41 µs/次